．There is a saying that ______ “Never put off until tomorrow what you can do today．”
| A．will go | B．goes | C．is going | D．has gone |
When firstto the market, these products enjoy great success.
| A．introducing | B．introduced | C．introduce | D．being introduced |
It is uncertain ______ side effect the medicine will bring about, although about two thousand patients have taken it.
| A．what | B．that | C．how | D．whether |
The English in the future will be quite different from the English of today. It is possible that some English words may even ________ completely.
| A．die down | B．die out | C．die off | D．die of |
Rainforests __________ and burned at such a speed that they will disappear from the earth in the near future.
| A．cut | B．are cut | C．are being cut | D．had been cut |
_______ the rain falling so hard, it becomes more and more difficult to carry on the rescue work.
| A．Since | B．As | C．With | D．For |