33. When a student asks_________it is worth staying up doing their lessons, a teacher may find it difficult to answer.
| A．that | B．what | C．whether | D．How |
It didn’t surprise us at all caused his success.
| A．why | B．that | C．how | D．what |
He called the police for help, that the problem was more than he could deal with.
| A．having been realized | B．realizing | C．realized | D．had realized |
Most of the students have hardly ever been to the Grand Canyon, __?
| A．haven’t they | B．have they | C．aren’t they | D．are they |
We had an anxious couple of weeks ______ for the results of the experiment.
| A．wait | B．to be waiting | C．waited | D．waiting |
I don’t think English is a language as Russian.
| A．more difficult | B．as difficult as | C．such difficult | D．as difficult |