1. if he minded helping her to fix the fax machine after he had finished his job that day

câu gián tiếp dạng yes/no question: asked sb if + mệnh đề dạng khẳng định và lùi 1 thì

2. what had been done to reduce the harmful effects of bad websites on teenagers

câu gián tiếp lùi 1 thì

3. were you, I would install the latest version of Windows for the computer

câu điều kiện loại 2 giả định không có thật ở hiện tại: If + S + Vqk, S + would + Vinf

4. should be used by the government to raise people's awareness of environmental protection

bị động: be Vp2 (by...)

5. By the time the office building started to catch fire, I had left my office

by the time + S + Vqk, S + had + Vp2: trước khi...làm gì thì...làm gì