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 |
Beyond ___stars, the astronaut saw nothing but ___ space.
| A．/…the | B．/…/ | C．the…/ | D．the…the |
Biology is ___.
| A．science of life | B．science of the life | C．the science of the life | D．the science of life |
Miss Smith is a close friend of ___.
| A．Mary mother’s | B．Mary mother | C．Mary’s mother’s | D．Mary’s mother’s |
Most of the wood ___ to make furniture.
| A．is used | B．are used | C．is use | D．are using |
My trousers are too old. I’ll have to buy ___.
| A．a new pair | B．a new one | C．a pair of | D．some new pair |