亲们这个英语句子怎么填空?

问题描述:

亲们这个英语句子怎么填空?
Martin is at work.He __________ at work since 8:30.

填:has been
根据 since 8:30可知,谓动用现在完成时,
at work 是介词短语,因此其前必须加上be动词.故填 has been .
句意:马丁在上班.从8:30起他一直在上班.