It won't be safe to use these stairs ... until they have them repaired

19/50

Mark the letter A, B, C, D on your answer sheet to indicate the correct answer to each of the following questions.

It won't be safe to use these stairs ________

until they have them repaired

before they repair them

after they will repair them

when they repaired them

Giải thích

Đáp án A

Tương lai đơn + before/when/after/ until + hiện tại đơn

Tạm dịch: Sẽ không an toàn khi sử dụng những cầu thang này đến khi họ sửa xong chúng.