lastweek用since还是for

last week用since不是for。因为last week是时间点用since而for是接时间段。中文意思是“自从上周以来。”

例如，自从上周以来，我们班运动员们都一直在为即将到来的校运动会忙着做准备。

Since last week, the athletes in our class have been busy preparing for the coming school sports meeting.