100 câu trắc nghiệm Thì quá khứ hoàn thành tiếp diễn (Past Perfect Continuous) có đáp án

 She was very tired. She ________ (type) letters all day long.

11/100

 She was very tired. She ________ (type) letters all day long.

has typed

has been typing

had been typing

had typed

Giải thích

Chọn đáp án: C