______ the traveler of carrying drugs, the customs official stopped him and went through his suitcase.
| A．To suspect | B．Being suspected |
| C．Suspecting | D．Suspected |
31．The fact that smoking is harmful to health is____most smokers are quite aware of．
| A．what | B．which | C．where | D．That |
30.It was_________ back home after the experiment.
| A．not until midnight did he go | B．until midnight that he didn’t go |
| C．not until midnight that he went | D．until midnight when he didn’t go |
29.An example of them is fraud, a crime _______ money is stolen by cheating others.
| A．which | B．that | C．what | D．Where |
28. Dr. Frank failed many times but he finally _____ to find a successful way to solve the problem.
| A．broke off | B．broke up | C．broke down | D．broke through |
27.---Where have you been?
---I got caught in traffic, otherwise I _______ here earlier.
| A．would be | B．have been | C．had been | D．would have been |