100 câu trắc nghiệm Thì quá khứ hoàn thành tiếp diễn (Past Perfect Continuous) có đáp án
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Before the phone call, she ________ on a business report.

75/100

Before the phone call, she ________ on a business report.

 

worked

had worked

was working

has been working

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Chọn đáp án: D