I watched the girl step off the sidewall,__the road,and__into the post office.
问题描述：
I watched the girl step off the sidewall,__the road,and__into the post office.
A crossed;disappear B cross;disappear C to cross;to diaappear D crossed;disappeared
2.i saw her working in the office this morning.She __back to his post without the doctor's permission .
A couldn't B coultn't have come C should have come D shouldn't have come
答
D crossed;disappeared
step,crossed,disappeared是并列谓语 都用过去式.step的过去式是原形.
2,D shouldn't have come should‘nt +现在完成时表示“本不该...”
没有医生的也许她本不该回去工作.