We thought there were 35 students in the dining hall, ______, in fact, there were 40.
| A．while | B．whether | C．what | D．which |
Achieving a high degree of proficiency in English as a foreign language is not a mysterious _____ without scientific basis.
| A．process | B．practice | C．procedure | D．program |
They were so far away that I couldn't _____ their faces clearly.
| A．see through | B．make up | C．see off | D．make out |
If the boy had _____ the dog alone it wouldn't have bitten him.
| A．set | B．left | C．had | D．put |
The generation _____ makes it difficult for parents to understand their children's opinions.
| A．division | B．gap | C．separation | D．interval |
With sufficient scientific information a manned trip to Mars should be _____.
| A．obtainable | B．potential | C．considerable | D．feasible |