なぜやるか
関係詞問題は Part5 で毎回2〜4問出題される頻出ジャンルです。選択肢に who / which / that / whose / where / what などが並び、「先行詞の種類（人か物か）」「文中の役割（主格か目的格か所有格か）」「制限用法か非制限用法か」を正確に判断して選ぶ問題です。
攻略の鍵は、選択肢の語を見た瞬間に「何が問われているか」を判断し、先行詞・空所の役割・カンマの有無を確認することです。
攻略法
①関係代名詞の選び方
| 先行詞 | 主格（S） | 目的格（O） | 所有格 |
|---|---|---|---|
| 人 | who / that | who(m) / that | whose |
| 物・事 | which / that | which / that | whose / of which |
| 人・物両方 | that | that | — |
制限用法（先行詞を限定）：the book that I read → カンマなし
非制限用法（補足説明）：Mr. Kim, who joined last month, ... → カンマあり・that は使えない
②関係副詞の選び方
| 語 | 意味 | 言い換え | 例 |
|---|---|---|---|
| where | 〜する場所 | at/in which | the office where I work |
| when | 〜する時 | at/in which | the day when he arrived |
| why | 〜する理由 | for which | the reason why she left |
| how | 〜する方法 | — | This is how it works. |
③特殊な関係詞
| 語 | 用法 | 例 |
|---|---|---|
| what | 「〜すること/もの」（先行詞を含む） | What matters is quality. |
| whoever | 「〜する人は誰でも」 | Whoever applies will be considered. |
| whichever | 「どちらでも」 | Whichever you choose is fine. |
| whatever | 「〜するものは何でも」 | Whatever happens, stay calm. |
| whether | 「〜かどうか」（間接疑問） | We discussed whether to proceed. |
④前置詞＋関係代名詞（フォーマル表現）
in which= whereat which= where（時間の場合はwhen）to whom= 誰に対してfor which= that/which + forof which= whose（物の場合）
⑤解き方
① 選択肢に関係詞（who/which/that等）が並んでいたら関係詞問題
② 先行詞を確認（人か物か・特定か不特定か）
③ カンマの有無を確認（カンマあり → that は不可）
④ 空所の役割を確認（主格S・目的格O・所有格・副詞的）
⑤ what / whoever 等は先行詞なし → 前に修飾する名詞がないか確認
やり方
| ステップ | 内容 |
|---|---|
| 1 | 攻略法の表を読み、関係詞の使い分けを整理する |
| 2 | 練習問題を解く（先行詞・カンマ・空所の役割を確認） |
| 3 | 間違えた問題は「なぜその関係詞か」を確認する |
| 4 | 正解できた問題も構造把握まで読んで根拠を確認する |
16問以上正解（80%）を目標にしてください。
練習問題（20問）
Q1. The company’s annual report, ------- was released to the public last week, showed a significant increase in revenue for the third consecutive year.
(A) that (B) which (C) who (D) what
Q1の解答・解説を見る
- (A) that → 非制限用法（カンマあり）では that は使えない（最重要ルール）
- (C) who → 先行詞が人の場合に使う。物（annual report）には使えない
- (D) what → 先行詞を含む名詞節を導く。すでに先行詞（annual report）があるので不可
S[The company’s annual report], which was released (to the public (last week)), V[showed] O[a significant increase in revenue] (for the third consecutive year).
Q2. Employees who are interested in applying for the overseas assignment should visit the human resources office, ------- they can obtain the necessary application forms and receive guidance.
(A) which (B) what (C) where (D) when
Q2の解答・解説を見る
- (A) which → 関係代名詞。ここでは “they can obtain forms” が完全な文であり、目的語が欠けていないため関係代名詞は不要
- (B) what → 先行詞を含む名詞節を導く。すでに先行詞がある
- (D) when → 時を表す関係副詞。先行詞が場所（office）なので不可
S[Employees (who are interested in applying for the overseas assignment)] V[should visit] O[the human resources office], where they can obtain the necessary application forms and receive guidance.
Q3. The engineering firm is currently seeking talented professionals ------- have extensive experience in developing large-scale infrastructure projects across multiple countries.
(A) who (B) whose (C) whom (D) which
Q3の解答・解説を見る
- (B) whose → 所有格。後ろに名詞が続くはず（”whose experience” など）。ここでは “have” が動詞として続く
- (C) whom → 目的格。後ろに主語＋動詞（SV）が続くはずだが、ここでは動詞 have が続いている（= 主格が必要）
- (D) which → 物・事を先行詞にとる。人（professionals）には使えない
S[The engineering firm] V[is seeking] O[talented professionals (who have extensive experience (in developing large-scale infrastructure projects (across multiple countries)))].
Q4. The company recently signed a contract with a construction firm ------- reputation for delivering high-quality projects on time is well established throughout the region.
(A) who (B) that (C) which (D) whose
Q4の解答・解説を見る
- (A) who → 主格または目的格の関係代名詞。後ろに名詞が続く所有格の位置には使えない
- (B) that → 所有格の用法はない（”that reputation” は独立した節になれない）
- (C) which → 主格または目的格の関係代名詞。所有格の機能はない
S[The company] recently V[signed] O[a contract] (with a construction firm (whose reputation (for delivering high-quality projects on time) is well established (throughout the region))).
Q5. ------- surprised the board of directors most at the annual review was the company’s unexpected growth in overseas markets during the second quarter of the fiscal year.
(A) That (B) Which (C) What (D) Who
Q5の解答・解説を見る
- (A) That → that節（”that S V”）も名詞節になれるが、”That surprised them most was …” のように、”that” が主語の述語（surprised）の主語になる構造は英語では非文法的。what が正しい
- (B) Which → 疑問詞として使うなら “Which surprised them most?” が疑問文になり、平叙文の主語位置には合わない
- (D) Who → 「誰が驚かせたか」という意味になり、文意が合わない（驚いたのはboard、驚かせたのは”the growth”）
S[What surprised the board (of directors) most (at the annual review)] V[was] O[the company’s unexpected growth (in overseas markets) (during the second quarter)].
Q6. ------- is selected for the position of regional director will be expected to oversee a team of twenty engineers and manage a substantial annual budget.
(A) Whoever (B) Whatever (C) Wherever (D) Whichever
Q6の解答・解説を見る
- (B) Whatever → 「〜するものは何でも」で物を指す。人（selected person）には不適切
- (C) Wherever → 「〜するところはどこでも」で場所を指す。文意に合わない
- (D) Whichever → 「どちらでも/どれでも」で限られた選択肢から選ぶ場合。ここは「選ばれた人は誰でも」という意味で使う
S[Whoever is selected (for the position of regional director)] V[will be expected] (to oversee a team (of twenty engineers) and manage a substantial annual budget).
Q7. Dr. Harper, ------- has been conducting groundbreaking research in the field of renewable energy for the past decade, will deliver the keynote address at the annual science conference.
(A) which (B) that (C) what (D) who
Q7の解答・解説を見る
- (A) which → 先行詞が物・事の場合に使う。人（Dr. Harper）には使えない
- (B) that → 非制限用法（カンマあり）では that は使えない
- (C) what → 先行詞を含む名詞節を導く。すでに先行詞 Dr. Harper があるので不可
S[Dr. Harper], who has been conducting groundbreaking research (in the field of renewable energy) (for the past decade), V[will deliver] O[the keynote address] (at the annual science conference).
Q8. The training manual ------- the new recruits received on their first day of orientation contains detailed procedures for every aspect of the customer service operation.
(A) who (B) that (C) what (D) whose
Q8の解答・解説を見る
- (A) who → 先行詞が人の場合に使う。物（training manual）には使えない
- (C) what → 先行詞を含む名詞節を導く。すでに先行詞（training manual）がある
- (D) whose → 所有格。後ろに名詞が必要だが、ここでは “S V” が続いている
S[The training manual (that the new recruits received (on their first day (of orientation)))] V[contains] O[detailed procedures] (for every aspect (of the customer service operation)).
Q9. The spring season is the time of year ------- the company receives the highest volume of customer orders and the entire logistics team is stretched to its maximum capacity.
(A) when (B) where (C) which (D) whose
Q9の解答・解説を見る
- (B) where → 場所の関係副詞。先行詞が時（time）なので不可
- (C) which → 関係代名詞。後ろが完全な文（S + V）なので目的語は欠けておらず、関係代名詞は不要（関係副詞が適切）
- (D) whose → 所有格の関係代名詞。後ろに名詞が続くはずだが、ここでは節が続いている
S[The spring season] V[is] C[the time (of year) (when the company receives the highest volume (of customer orders) and the entire logistics team is stretched (to its maximum capacity))].
Q10. All products ------- are displayed in the clearance section of the store have been reduced by at least forty percent for the final week of the annual sale.
(A) who (B) whose (C) that (D) what
Q10の解答・解説を見る
- (A) who → 先行詞が人の場合に使う。物（products）には使えない
- (B) whose → 所有格。後ろに名詞が必要だが、ここでは動詞（are）が続いている
- (D) what → 先行詞を含む名詞節を導く。すでに先行詞（All products）があるので不可
S[All products (that are displayed (in the clearance section (of the store)))] V[have been reduced] (by at least forty percent) (for the final week (of the annual sale)).
Q11. The state-of-the-art conference room, ------- more than 200 delegates gathered for the opening ceremony, was equipped with simultaneous interpretation systems in eight languages.
(A) that (B) which (C) whose (D) in which
Q11の解答・解説を見る
- (A) that → 非制限用法（カンマあり）では that は使えない
- (B) which → “which delegates gathered” にすると、gathered の目的語が which になるが、gather は自動詞で目的語をとらないため不適切。”in which” が必要
- (C) whose → 所有格。後ろに名詞が必要だが、ここでは節（SV）が続いている
S[The state-of-the-art conference room], in which more than 200 delegates gathered (for the opening ceremony), V[was equipped] (with simultaneous interpretation systems (in eight languages)).
Q12. The company hired a senior consultant ------- expertise in digital marketing strategies has helped several major corporations significantly improve their online presence.
(A) that (B) whose (C) who (D) which
Q12の解答・解説を見る
- (A) that → 所有格の用法はない
- (C) who → 主格または目的格。後ろに名詞（expertise）が続く所有格の位置には使えない
- (D) which → 所有格の用法はない（物の所有格には “of which” を使う）
S[The company] V[hired] O[a senior consultant (whose expertise (in digital marketing strategies) has helped several major corporations (significantly improve their online presence))].
Q13. The operations manager gave a clear presentation to the team explaining ------- the new inventory management system would reduce errors and improve overall efficiency in the warehouse.
(A) that (B) which (C) what (D) how
Q13の解答・解説を見る
- (A) that → “explaining that S V” は「〜ということを説明する」という意味になり、”how” の「どのように」という方法の意味が失われる
- (B) which → “which the system would reduce” では関係代名詞として使い、”errors” の後に先行詞が必要になるが不自然
- (C) what → “explaining what the system would reduce” = 「何を削減するかを説明する」という意味になり、「どのように削減するか」という方法の意味が出ない
S[The operations manager] V[gave] O[a clear presentation] (to the team) (explaining how the new inventory management system would reduce errors and improve overall efficiency (in the warehouse)).
Q14. The marketing team successfully launched the new product line last spring, ------- resulted in a thirty-five percent increase in the company’s overall market share.
(A) which (B) that (C) what (D) whose
Q14の解答・解説を見る
- (B) that → 非制限用法（カンマあり）では that は使えない
- (C) what → 「〜したこと」という名詞節になるが、すでに文は完結しており what を挿入する余地がない
- (D) whose → 所有格。後ろに名詞が必要だが、ここでは動詞 resulted が続いている
S[The marketing team] successfully V[launched] O[the new product line] (last spring), which V[resulted] (in a thirty-five percent increase (in the company’s overall market share)).
Q15. The construction contract will be awarded to ------- company submits the most competitive bid that fully meets all of the technical specifications and delivery requirements.
(A) whoever (B) whatever (C) wherever (D) whichever
Q15の解答・解説を見る
- (A) whoever → 人を表す複合関係詞。後ろに名詞（company）を修飾する形では使えない（”whoever company” は不可）
- (B) whatever → 「〜するものは何でも」で物を指す。名詞 company を修飾する用法では不自然（”whatever company” は文法的に可だが “whichever” の方が適切）
- (C) wherever → 「〜する場所はどこでも」で場所を指す。company を修飾できない
S[The construction contract] V[will be awarded] (to whichever company (submits the most competitive bid (that fully meets all (of the technical specifications and delivery requirements)))).
Q16. The candidate ------- the hiring committee selected for the director of international operations position has over fifteen years of experience managing multinational teams.
(A) who (B) whom (C) whose (D) which
Q16の解答・解説を見る
- (A) who → 主格の関係代名詞。ここでは selected の目的語位置なので本来は whom が正しい（TOEIC では whom が問われる）
- (C) whose → 所有格。後ろに名詞が必要だが、ここでは “S V” が続いている
- (D) which → 物・事を先行詞にとる。人（candidate）には使えない
S[The candidate (whom the hiring committee selected (for the director (of international operations) position))] V[has] O[over fifteen years of experience] (managing multinational teams).
Q17. The primary reason ------- the product launch was postponed by nearly three weeks was the unexpected shortage of essential components from the company’s main supplier.
(A) why (B) when (C) that (D) which
Q17の解答・解説を見る
- (B) when → 時を表す関係副詞。先行詞が理由（reason）なので不可
- (C) that → 関係代名詞として使う場合、後ろが “S + V（postponed）” の完全な文であり、目的語も欠けていない。that は関係副詞の代わりには使えない（”the reason that” は口語では使われるが、TOEICでは why が正式）
- (D) which → 関係代名詞。”the product launch was postponed” は完全な文（S+V）なので、which が目的語として入る余地がない。前置詞を伴う “for which” なら可能だが、選択肢は “which” 単独
S[The primary reason (why the product launch was postponed (by nearly three weeks))] V[was] C[the unexpected shortage (of essential components) (from the company’s main supplier)].
Q18. All staff members should carefully review ------- guidelines are distributed by the compliance officer prior to the start of the new regulatory reporting procedures next month.
(A) whoever (B) wherever (C) however (D) whatever
Q18の解答・解説を見る
- (A) whoever → 人を指す複合関係詞。名詞 guidelines（物）を修飾できない
- (B) wherever → 場所を指す複合関係詞。guidelines を修飾できない
- (C) however → 「どのように〜しても」という副詞節を導く。名詞を修飾する形容詞的用法はない
S[All staff members] V[should review] O[whatever guidelines (are distributed (by the compliance officer) (prior to the start (of the new regulatory reporting procedures (next month))))].
Q19. The new employee handbook includes a clear set of protocols ------- all requests for overtime compensation must be submitted through the official online portal.
(A) by which (B) for whom (C) to which (D) of which
Q19の解答・解説を見る
- (A) by which → “submitted by” は動作主（〜によって）を示す。ここでは「〜に提出する（方向）」なので to が適切
- (B) for whom → whom は人を先行詞とする。先行詞は protocols（物）なので whom は不可
- (D) of which → “of the protocols” になるが、”submitted of protocols” は不自然
S[The new employee handbook] V[includes] O[a clear set (of protocols) (to which all requests (for overtime compensation) must be submitted (through the official online portal))].
Q20. Senior management has not yet reached a final decision ------- the company’s new regional headquarters will be located in the downtown business district or on the outskirts of the city.
(A) what (B) whether (C) which (D) how
Q20の解答・解説を見る
- (A) what → 「何か」を表す間接疑問詞。「どこに置くかを決める（what）」は意味的に合わない。また後ろに “or” を伴う二者択一の構造にも合わない
- (C) which → 「どちらが〜か」という疑問詞として使う場合は “which of the two locations” のような形が必要。ここの構造とは合わない
- (D) how → 「どのように」という方法を問う。AかBかという二者択一の決定には使わない
S[Senior management] has not yet V[reached] O[a final decision] (as to whether the company’s new regional headquarters will be located (in the downtown business district) or (on the outskirts of the city)).
| 問題 | 正解 | カテゴリ |
|---|---|---|
| Q1 | (B) which | 非制限用法・物（カンマあり） |
| Q2 | (C) where | 関係副詞・場所 |
| Q3 | (A) who | 制限用法・人・主格 |
| Q4 | (D) whose | 所有格（人・組織） |
| Q5 | (C) What | 名詞節・主語節 |
| Q6 | (A) Whoever | 複合関係詞・人 |
| Q7 | (D) who | 非制限用法・人（カンマあり） |
| Q8 | (B) that | 制限用法・物・目的格 |
| Q9 | (A) when | 関係副詞・時 |
| Q10 | (C) that | 制限用法・物・主格 |
| Q11 | (D) in which | 前置詞＋関係代名詞 |
| Q12 | (B) whose | 所有格（人） |
| Q13 | (D) how | 間接疑問・方法 |
| Q14 | (A) which | 非制限用法・前節全体を先行詞 |
| Q15 | (D) whichever | 複合関係詞・物（形容詞的） |
| Q16 | (B) whom | 制限用法・人・目的格 |
| Q17 | (A) why | 関係副詞・理由 |
| Q18 | (D) whatever | 複合関係詞・物（形容詞的） |
| Q19 | (C) to which | 前置詞＋関係代名詞 |
| Q20 | (B) whether | 間接疑問・二者択一 |
正解数の分布：A×5 / B×5 / C×5 / D×5