Scientists say it may be five or six years _______ it is possible to test this medicine on human patients.
| A．since | B．after | C．before | D．when |
There is even an animal whose tail will _____ so that it can run away if someone grabs it.
| A．break down | B．break up | C．break out | D．break off |
-----What were you up to when she dropped in?
------I______ for a while and _____ some reading.
| A．had played ; did | B．played; did |
| C．had played :was going to do | D．was playing; was going to do |
Nowadays the belief has become common ______ sea food and fruit rich in vitamin C should never be eaten at the same meal.
| A．that | B．how | C．when | D．/ |
Stop that foolish clapping._____ from you and you’ll celebrate Christmas by losing your position!
| A．Another sound | B．Hear another sound |
| C．Making another sound | D．Another sound to be heard |
----How did you find your first visit to Heilongtan Lake?
-----_______.
| A．taking a bus. | B．Oh, wonderful, indeed. |
| C．I went there alone. | D．A classmate of mine showed me the way |