________ Sandy's damage is unlikely to last long, it would apparently hurt the total economic output of the fourth quarter.
| A．Since | B．Before |
| C．Unless | D．Although |
It is said that in Australia there is more land than the government knows _______.
| A．it what to do with | B．what to do it with |
| C．what to do with it | D．to do what with it |
The research is so designed that once _______ nothing can be done to change it.
| A．begins | B．having begun | C．beginning | D．begun |
Having a trip abroad is certainly good for the old couple, but it remains _______ whether they will enjoy it.
| A．to see | B．to be seen | C．seeing | D．seen |
_______ such heavy pollution already, it may now be too late to clean up the river.
| A．Having suffered | B．Suffering | C．To suffer | D．Suffered |
Robert is said _______ abroad, but I don’t know what country he studied in.
| A．to have studied | B．to study |
| C．to be studying | D．to have been studying |