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

We (sleep) for 12 hours when he woke us up.

88/100

We (sleep) for 12 hours when he woke us up.

Had been sleeping

Had slept

Slept

Were sleeping

Giải thích

Chọn đáp án: A