．—______ I lock the lab before I go home?
—Don’t bother．I’ll check it myself later．
A．May B．Must C．Can D．Shall
．Interestingly in some parts of the world, women are expected to earn money _____ men work at home and raise their children．
A．but B．though C．because D．while
Leaders of many countries have been trying to _____ what it is that makes China develop so fast in recent years．
A．carry out B．figure out C．watch out D．make out
I’m not sure whether I will have anything else to do this evening．_____, I will try every possible means to come to your birthday party．
A．Even though B．If so C．Anyhow D．Instead
My toothache is killing me．I _____ it _____ away．But now it’s getting worse and worse．
A．think; is going B．thought; was going
C．have thought; is going D．had thought; had gone
---The exam starts at 9:00 tomorrow morning．
---___________ I fail to arrive there on time?
A．What if B．As if C．Only if D．Even if
