なぜやるか
because / although / when / if などの接続詞で始まる副詞節は、文の骨格（主節の S + V）を隠す最大の原因の一つです。この塊を < > で囲んで外す練習をすると、「どこが主節でどこが従属節か」が一瞬で分かるようになります。また接続詞問題（Part5最頻出）では「この接続詞の後ろに S + V があるか、名詞だけか」の判断が核心であり、副詞節を囲う練習がその感覚を養います。このLesson 7を終えると、副詞節を含む複雑な文の主節を素早く取り出せるようになります。
やり方
副詞節を作る主な接続詞
時：when / while / before / after / as soon as / until / once
理由：because / since / as / now that
条件：if / unless / provided that / as long as
譲歩：although / though / even though / even if / while
対比：whereas / while
囲む手順
- 接続詞を見つける
- 接続詞から「節の終わり（コンマまたは文末）」まで < > で囲う
- < > を外して主節（S + V + O/C）を確認する
副詞節の位置
文頭の副詞節：<Although demand dropped,> sales targets were met.
文末の副詞節：Sales targets were met <although demand dropped>.
例文トレーニング
文1｜文頭の副詞節（理由）
原文: <Because the delivery was delayed (by the logistics provider),>
the project manager notified all stakeholders immediately.
< > = Because the delivery was delayed by the logistics provider ← 理由
S = the project manager
V = notified
O = all stakeholders
→ < > を外すと主節「the project manager notified all stakeholders immediately.」が浮かび上がる。
文2｜文末の副詞節（条件）
原文: The new pricing model will be implemented (next quarter)
<if the pilot program yields positive results.>
S = The new pricing model
V = will be implemented
( ) = next quarter ← いつ
< > = if the pilot program yields positive results ← 条件
→ < > が文末にある場合もコンマなしで続く。
文3｜文頭の副詞節（譲歩）
原文: <Although the initial budget estimate had been underestimated (by fifteen percent),>
the project was completed (within the revised financial constraints).
< > = Although the initial budget estimate had been underestimated ← 譲歩
( ) = by fifteen percent ← < >の内部
S = the project
V = was completed
( ) = within the revised financial constraints
→ < > を外すと「the project was completed within the revised financial constraints.」が残る。
文4｜時の副詞節（as soon as）
原文: <As soon as the regulatory approval was granted,>
the company launched the new product line (in all major markets).
< > = As soon as the regulatory approval was granted ← 時（〜するとすぐに）
S = the company
V = launched
O = the new product line
( ) = in all major markets
→ as soon as から節の終わり（コンマ）まで全体が < >。
文5｜副詞節と前置詞句が共存する文
原文: <While the headquarters team was reviewing the annual report,>
the regional managers submitted additional data (from their respective offices)
(before the final deadline).
< > = While the headquarters team was reviewing the annual report ← 時・対比
S = the regional managers
V = submitted
O = additional data
( ) = from their respective offices ← dataを修飾
( ) = before the final deadline ← 時
→ < > と ( ) を外すと「the regional managers submitted additional data.」が残る。
実戦問題
構造を分解しながら空所を埋めましょう。
Q1. ------- the company had invested heavily in staff training, overall productivity declined significantly during the third quarter.
(A) Because (B) Due to (C) Although (D) As a result of
解答・解説を見る
構造メモ:
[-------] the company had invested heavily (in staff training),
overall productivity declined significantly (during the third quarter).
空所の後ろ = the company had invested（S + V あり）→ 接続詞が入る
文意：「研修に投資したにもかかわらず、生産性が低下した」→ 譲歩
正解: (C) Although
空所の後ろに S + V（the company had invested）があるため接続詞が必要。文意が「〜にもかかわらず」の譲歩なので although が正しい。
(A) Because：理由「〜なので」を表し文意に合わない。(B) Due to：前置詞句で後ろに名詞が必要（S + V は不可）。(D) As a result of：前置詞句で後ろに名詞が必要。
Q2. The temporary staff will be retained ------- the peak sales season concludes at the end of next month.
(A) despite (B) until (C) because of (D) owing to
解答・解説を見る
構造メモ:
The temporary staff will be retained [-------]the peak sales season concludes (at the end of next month).
空所の後ろ = the peak sales season concludes（S + V あり）→ 接続詞が入る
文意：「ピークシーズンが終わるまで（継続）」→ until
正解: (B) until
後ろに S + V（the peak sales season concludes）があるため接続詞が必要。「〜するまで（継続）」の意味の until が正しい。
(A) despite：前置詞で後ろに名詞が必要。(C) because of：前置詞句で後ろに名詞が必要。(D) owing to：前置詞句で後ろに名詞が必要。
Q3. ------- the management team announces the new organizational structure, all department heads are required to attend the briefing session.
(A) Once (B) Despite (C) Because of (D) In spite of
解答・解説を見る
構造メモ:
[-------] the management team announces the new organizational structure,
all department heads are required (to attend the briefing session).
空所の後ろ = the management team announces（S + V あり）→ 接続詞が入る
文意：「発表されたら / 発表され次第」→ 時の接続詞
正解: (A) Once
後ろに S + V があるため接続詞が必要。once「〜したら / 〜すると（その後）」は時の接続詞で「発表され次第、全員出席が義務付けられる」という文意に合う。
(B) Despite：前置詞で後ろに名詞が必要。(C) Because of：前置詞句で後ろに名詞が必要。(D) In spite of：前置詞句で後ろに名詞が必要。
Q4. The HR team will release the updated benefits package ------- the board of directors has formally approved the proposed revisions.
(A) during (B) because of (C) in addition to (D) after
解答・解説を見る
構造メモ:
The HR team will release the updated benefits package [-------]the board of directors has formally approved the proposed revisions.
空所の後ろ = the board of directors has formally approved（S + V あり）
→ 接続詞が入る。文意：「理事会が承認した後に」
正解: (D) after
後ろに S + V があるため接続詞として使える after「〜した後に」が正しい。after は前置詞にも接続詞にもなるが、ここでは S + V を従えているので接続詞用法。
(A) during：前置詞で後ろに名詞が必要（動名詞は可だが has approved は節）。(B) because of：前置詞句で後ろに名詞が必要。(C) in addition to：前置詞句で後ろに名詞が必要。
Q5. ------- the sales figures for the domestic market remained strong, the company still decided to accelerate its international expansion plans.
(A) Because (B) Due to (C) Even though (D) As a result of
解答・解説を見る
構造メモ:
[-------] the sales figures (for the domestic market) remained strong,
the company still decided (to accelerate its international expansion plans).
空所の後ろ = the sales figures remained（S + V あり）→ 接続詞が入る
文意：「数字が好調だったにもかかわらず、さらに拡大を決めた」→ 譲歩
正解: (C) Even though
後ろに S + V があるため接続詞が必要。「〜であるにもかかわらず」の譲歩を表す even though が正しい。
(A) Because：理由「〜なので」で文意が逆になる。(B) Due to：前置詞句で後ろに名詞が必要。(D) As a result of：前置詞句で後ろに名詞が必要（「〜の結果として」の意味も文脈に合わない）。
正解一覧
| 問題 | 正解 |
|---|---|
| Q1 | (C) |
| Q2 | (B) |
| Q3 | (A) |
| Q4 | (D) |
| Q5 | (C) |