Experts are trying to work out a plan to deal with the problems caused by global warming ______ it is too late.
| A．when | B．if | C．before | D．until |
Nuclear ______ be really dangerous at times even though it’s a nice energy in general.
| A．shall | B．should | C．can | D．Must |
When reading English novels, I often idiomatic expressions that I can't understand．
| A．come across | B．go over |
| C．get across | D．take over |
Hardly _when they realized that it was too late to catch the last train．
| A．the clock had struck twelve |
| B．the clock had been struck twelve |
| C．had the clock been struck twelve |
| D．had the clock struck twelve |
The Obama government has reformed on tax system.What people doubt is ______ it will do them any good．
| A．that | B．whether | C．why | D．What |
Everything seemed to be going_______ for the first two days after I moved to New York.
| A．vividly | B．generally | C．frequently | D．Smoothly |