--Can I call you back at two o’clock this afternoon?
---- I’m sorry , but then I ______ to Beijing . How about five ?
| A．fly | B．will be flying | C．will fly | D．am flying |
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 |
26．—May I ask a question after class，sir?
—____，but not during my lunch break．
| A．Take it easy | B．No way | C．Certainly | D．Go ahead |