If there ______ no water, there ______ no life on the earth.
| A．is, would be. | B．was, was. | C．were, would be. | D．were, would have. |
Mass deaths of birds were not unheard of, but they normally happened unnoticed at sea or in rural areas away from towns. Many birds are weak and die in winter _______ food is scarce.
| A．which | B．what | C．when | D．how |
There was no sign _______ they had died from diseases such as bird flu - the main worry in such cases. Among the theories was _______ a truck had collided（碰撞）with the crowd.
| A．/; that | B．that; that | C．that; which | D．that; / |
Early this year, thousands of migrant _______ workers cancelled their insurance due to the lack of _______ policy to transfer insurance between difference regions.
| A．the; the | B．the; a | C．/; the | D．/; a |
He didn’t make clear when and where the meeting would be held.
A. this B. that C. it D these
It's high time that we students ______ even harder at our lessons as the national entrance examination is coming nearer.
| A．work | B．will work | C．worked | D．have to work |