過去進行形 助動詞+受け身
各組の英文がほぼ同じ意味になるよう，空欄に適切な単語を入力しなさい。
1．We couldn’t play golf because of rain last Sunday.
We couldn’t play golf （ ）（ ）（ ）raining last Sunday.
この前の日曜は雨が降っていたのでゴルフができなかった。（過去進行形）
2. They must discuss the problem soon.
The problem （ ）（ ）（ ） soon by them.
その問題は彼らによってすぐに議論されなくてはならない。（助動詞＋受け身）
英語が苦手すぎて全然わかんないのでわかる方お願いします。
回答
This is not a piece of advice to you I'm talking to myself for my practice of writing skills.
1．We couldn't play golf because of rain last Sunday.
We couldn't play golf （because）（it）（was）raining last Sunday.
We couldn't play golf because it was raining last Sunday.（ past progressive ）
We couldn't play golf it had been raining last Sunday.（ past perfect progressive ）
2. They must discuss the problem soon.
The problem （must）（be）（discussed） soon by them.
The problem must be discussed soon by them.（ auxiliary verb + passive voice ）
3. They should have discussed the problem soon.（ auxiliary verb + past perfect tense + passive voice ）
The problem （should）(have)（been）（discussed） soon by them.
The problem should have been discussed soon by them.