_____is known to us all is that we should do as much as we can ______ stop the pollution of the environment.
| A．It; help | B．What; to help | C．As ; to help | D．That ; help |
________ is known to everybody, Taiwan is a part of China. We must unify it.
| A．It | B．As | C．Which | D．What |
The time is not far away ________ modern communications will become widespread in China’s vast countryside.
| A．as | B．when | C．until | D．before |
I hope that the little ________ I have been able to do does good to them all.
| A．which | B．what | C．that | D．when |
I hope that the little ________ I have been able to do does good to them all.
| A．which | B．what | C．that | D．when |
There are several research centers in China ________ a certain disease called Bird Flu is being studied.
| A．which | B．where | C．when | D．what |