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 |
More and more people have got to know the importance of the English study. ______, about six people in ten in this city are able to speak a little English.
| A．Believe it or not | B．As a matter of fact | C．As a result | D．In return |
It is only ______ you understand what your parents do to you ______ you can improve your relationship with your parents.
| A．that; what | B．when; that | C．which; where | D．how; what |
---When did you get to know each other ?
----It was in 2008___we spent summer vocation together.
| A．that | B．when | C．before | D．since |
Many parents have called head teachers to know ______ their children are getting along well with everything in the school.
| A．if | B．how | C．that | D．where |