Even scientists cannot completely ________for the strange behaviors of the animals before an earthquake. （原创）
| A．spot | B．explain | C．call | D．account |
— I put him down for a well-educated man.
—______ ?
— I mean that he's a well-educated man.
| A．I beg your pardon | B．Speak louder, will you |
| C．What’s that | D．Will you repeat word for word |
The silence of the library is sometimes broken by a sudden cough or the sound of pages______.
| A．turning | B．turned | C．being turned | D．having turned |
Wang Pin is an advanced worker in our company. He _______ for four years in Yangzhou University.
| A．studied | B．has studied | C．had studied | D．has been studying |
When it______ air pollution, Beijing faces the three “C” s-----cars，coal and construction，which lead to Beijing's thick air pollution.
| A．refers to | B．comes to | C．happens to | D．speaks to |
______ it have been the failure to pick up directions from the ground control that caused the air crash?
| A．Must | B．Could | C．Would | D．Should |