Shopping on line can provide ____ convenience and choice, but not ____ websites are safe enough for shopping.
| A．either; both | B．neither; any | C．both; both | D．both; all |
My mind wasn’t on what he was saying so I’m afraid I _______ half of it.
| A．was missing | B．had missed |
| C．will miss | D．missed |
The first use of atomic weapons was in 1945.And their power _______ increased enormously ever since.
| A．is | B．was |
| C．has been | D．had been |
They _______ on the program for almost one week before I joined them,and now we _______ it as no good results have come out so far.
| A．had been working; are still working |
| B．had worked; were still working |
| C．have been working; have worked |
| D．have worked; are still working |
—Would you like another sandwich?
—Another sandwich? I _______ my first one yet.
| A．haven’t had | B．hadn’t had |
| C．didn’t have | D．don’t have |
The crazy fans _______ patiently for two hours, and they would wait till the movie star arrived.
| A．were waiting | B．had been waiting |
| C．had waited | D．would wait |