When he came in, I happened __________ my experiment in the lab.
| A．to do | B．to be doing |
| C．to have done | D．to be done |
This is one of the experiments __________ in our laboratory.
| A．being made |
| B．making |
| C．to make |
| D．having made |
As we all know，__________ Siberian tiger is __________ endangered species.
| A．/；an |
| B．the; the |
| C．a; / |
| D．the; an |
I am __________ with living with a man of this kind.
| A．eat up |
| B．eaten up |
| C．feed up |
| D．fed up |
The poor child who lost his parents in an accident was __________ by a kind-hearted villager.
| A．put up |
| B．brought up |
| C．given up |
| D．taken up |
The present situation is very complex, so I think it will take me some time to __________ its reality.
| A．make up |
| B．figure out |
| C．look through |
| D．put off |