A number of sheep ___ seen by us when we passed the field A is B are C was D were A number of 表示许多 后面的sheep是单复数同型所以没有加S 因为是when we passed the field(当我们路过这个原野的时候看见的)`而且我们已经路过这个原野叻(passed) 所以用过去式并且是复数形式的were
She thinks she can get there on time,___ she? A can B doesn't C can't D does 逗号前面:她认为她可以按时到达那里, 后面则为反问:不是吗?(难道她卟可以吗?)所以用can't she?