関係詞
制限/非制限用法とコンマ運用を区別。
先行詞を正しく修飾し、冗長・曖昧さを避ける。
⚠️ひっかけ注意 — よくある失点パターン
- that は非制限用法（コンマ付き）不可。
- 前置詞の直後に that は置けない（✕ to that → ○ to which / whom）。
- who と whom：前置詞の後や動詞の目的語は whom（試験では whom を推奨）。
- what は先行詞を取らない（= the thing which）。✕ the reason what → ○ the reason why/that/for which。
- the reason is because は冗長。→ the reason is that / We revised the policy because ...
- where/when は「場所/時」を表す名詞にだけ用いる。抽象名詞には in which / at which などに置換。
- 非制限の , which は直前の名詞だけでなく前文全体を受けることがある（誤解を招かないよう配置）。
ポイント別演習
制限用法（無コンマ）
The policy that was updated last week will apply.
The policy ___ was updated last week will apply to all teams.
Employees ___ work remotely must follow the security protocol.
The book ___ I bought yesterday is very informative.
The technician ___ fixed the issue is on vacation now.
The candidates ___ we interviewed were all highly qualified.
The training program ___ we completed last month was very effective.
The client to ___ we sent the invoice has confirmed payment.
非制限用法（コンマ）
Our CEO, who joined in 2018, will visit Tokyo.
Mr. Tanaka, ___ has worked here for 20 years, is retiring next month.
The seminar, ___ was held last week, attracted 200 participants.
Our CEO, ___ joined in 2018, will visit Tokyo next month.
The new platform, ___ was launched in April, has gained traction.
Our headquarters, ___ is located in Tokyo, has expanded recently.
Ms. Chen, ___ I mentioned earlier, will lead the session.
The keynote speaker, ___ I introduced earlier, has won several awards.
関係副詞
the year when / the place where / the reason why
This is the office ___ Ms. Lee works.
Tell me the day ___ you would like to schedule the meeting.
2021 was the year ___ we expanded to Europe.
That is the reason ___ we revised the policy.
The factory ___ our products are manufactured is in Vietnam.
These are the conditions under ___ we operate.
The way ___ he handled the crisis impressed everyone.
whose の所有
an author whose books sell well
We chose a vendor ___ quote was significantly lower.
Mr. Brown, ___ son works at our Tokyo office, will visit next week.
The startup ___ founders are former Google engineers raised $50M.
The author ___ books are translated into 20 languages will visit Japan.
We thanked the volunteers ___ help made the event successful.
Tokyo, ___ skyline is instantly recognizable, attracts many tourists.
We notified customers ___ data were affected by the outage.
I met a colleague ___ work I admire greatly.
Companies ___ employees work overtime regularly often have higher turnover.