I have always regretted ______ harder at school.
| A．not to study | B．to not study |
| C．having not studied | D．not having studied |
---- The woman biologist stayed in Africa studying wild animals for 13 years before she returned.
---- Oh, dear! She _______ a lot of difficulties!
| A．may go through | B．might go through |
| C．ought to have gone through | D．must have gone through |
In our childhood, we were often _______ by Grandma to pay attention to our table manners.
| A．demanded | B．reminded | C．allowed | D．hoped |
They _______ on the program for almost one week before I joined them, and now we ________ it as no good results have come out so far.
| A．had been working; are still working | B．had worked; were still working |
| C．have been working; have worked | D．have worked; are still working |
David has won the first prize in singing; he is still very excited now and feels________ desire to go to bed.
| A．the most | B．more | C．worse | D．the least |
________ in the mountains for a week, the two students were finally saved by the local police
| A．Having lost | B．Lost | C．Being lost | D．Losing |