—You’re coughing badly，Martin. Why not give up smoking?

—Give up smoking？Easier said than done，Amy. Once you ______ the habit of smoking，it is very hard for you to ______.

A．keep up; break it away

B．take up; drop it out

C．pick up; get rid of it

D．build up; do away with it

船长下达弃船命令后，机舱值班人员未得到船长（）完车通知，不得离开岗位。

A.一次

B.两次

C.三次

D.四次