Many experts agree that once these treasures are _______ to the air, great harm will be done to them. So they think it better not to unearth the treasures.
| A．exposed | B．threatened | C．constructed | D．conserved |
It is usually warm in my hometown in April, but it ________ be rather cold sometimes.
| A．can | B．must | C．would | D．should |
You should be ________ a diet; otherwise you will get fatter and fatter.
| A．at | B．in | C．on | D．with |
The student _____ from the training so much that he was _____ the first prize in the game.
| A．benefited; awarded | B．awarded; benefited |
| C．gained; earned | D．earned; gained |
Some students even have no idea of they are studying, so they waste much time playing.
| A．what | B．when | C．why | D．where |
If you ________ smoke in the room, please keep the windows open.
| A．should | B．may | C．shall | D．must |