Who do you think we should have______to Shanghai to visit the 2010 World Expo?
| A．to go | B．gone | C．going | D．go |
Though ______, many laws of nature exist.
| A．not having been discovered | B．having not been discovered |
| C．not having discovered | D．having not discovered |
While prices are rising so fast，many people are working out ways to________their expenses.
| A．cut down | B．put down | C．turn down | D．settle down |
The course about Chinese food attracts over 100 students per year, ________ up to half are from overseas.
| A．in which | B．for whom | C．with which | D．of whom |
here yesterday, he could have seen Jackie Chen.
| A．If Bob has come | B．If Bob came |
| C．Had Bob come | D．If Bob should come |
Among the many dangers_-- sailors have to face , probably the greatest of all is fog .
| A．which | B．what | C．where | D．when |