`37)` It takes my mother three hours to do the housework everyday.

`->` It take sb khoảng thời gian to Vinf : Nó lấy ai đó bao lâu để làm gì

`38)` If the telephone hadn't been invented , we couldn't have talked to each other so easily whenever we want.

`->` Câu điều kiện loại 3

`39)` The hospital which has three hundred rooms is being built

`->` Câu có chứa đại từ quan hệ "which" chỉ vật

`40)` I suggest that energy-saving appliances should be used instead of ordinary ones to save energy

`->` suggest that sb should do sth : gợi ý ai đó nên làm gì

$\text{37 It takes my mother three hours to do the housework every day.}$

$\text{It takes Sb khoảng thời gian to Vinf : tốn bao nhiêu thời gian để làm gì.}$

$\text{38 If the telephone hadn't been invented, we couldn't have talked to each other so easily whenever we want.}$

$\text{CĐK loại 3: If+ S+ had+ Vp2, S+ would/ could/ should(not)+ have+ Vp2.}$

$\text{39 The hospital which has three hundred rooms are being built.}$

$\text{Câu có đại từ quan hệ "which" chỉ vật:}$

$\text{N(thing)+ which+ S+ V.}$

$\text{N(thing)+ which+ V+ O.}$

$\text{40 I suggest that energy-saving appliances should be used instead of ordinary ones to save energy.}$

$\text{S+ suggest that sb should do sth : gợi ý ai đó nên làm gì.}$