104 câu trắc nghiệm Thì quá khứ hoàn thành (Past Perfect) có đáp án

When he reached the summit, he realized he ________ his camera at the base.

53/104

When he reached the summit, he realized he ________ his camera at the base.

had left

leaves

left

leaving

Giải thích

Chọn đáp án: A