The shop doesn’t open until 11 a. m.,________ it loses a lot of business.
| A．for | B．or | C．but | D．so |
I have been told to donate blood by the health expert __________ I need some in the medical treatment one day.
| A．even though | B．as if |
| C．in case | D．now that |
Nelson Mandela _________ his life to fighting for a free society________ all people live together in harmony.
| A．devoted; which | B．spent; in which |
| C．devoted; in which | D．spent; where |
The number of various educational programs is increasing, _______ important roles have been realized by more and more people.
| A．whose | B．where | C．which | D．that |
It is dangerous to take ________ from rain under a tree especially during a summer rainstorm.
| A．cover | B．shelter | C．hiding | D．advantage |
--- What do you think of the grammar book?
--- Oh, it really is ________ useful reference book, which is worth reading ________ second time.
| A．a; a | B．an; the | C．an; | D．the; the |