5000 câu trắc nghiệm Tiếng Anh 9 có đáp án - Phần 3

When boarding the plane, many passengers were annoyed because they

14/20

When boarding the plane, many passengers were annoyed because they ________ waiting in the airport for three ad a half hours.

are

were

have been

had been

Giải thích

Chọn đáp án D