我到办公室的时候,他们已经开始工作了 用英文怎么说
问题描述：
我到办公室的时候,他们已经开始工作了 用英文怎么说
by the time I arrived at the office,they ____ _____ _____already
答
问题补充：
by the time I arrived at the office,they _had___ started_____ _working____already
When I got to the office,they had begun to work