患者，女性，50岁。消瘦，近1个月粪便中有脓血和黏液，肛门坠胀感。检查中首先考虑的是（）。

A.肠镜检查

B.肛门检查

C.B超

D.CT

E.CEA测定

-Must we hand in the money for the tickets now?

-No, you __________.[ ]

A. mustn't

B. can't

C. needn't

D. may not