After ________in the research for so many years，the scientist succeeded in finding the result at last.
| A．buried | B．being buried | C．having buried | D．having been buried |
The door _____ open, no matter how hard she pushes.
| A．doesn’t | B．can’t | C．won’t | D．shouldn’t |
When I first met Doris I didn’t like her, but I ______ my mind.
| A．have changed | B．change | C．had changed | D．would change |
An air crash accident happened to the plane, ______.
| A．nobody alive | B．nobody was alive | C．and nobody alive | D．where nobody alive |
I wondered what difficulty he had _____ the plan.
| A．to carry out | B．carrying out | C．carried out | D．with carrying out |
_______ confidence and patience, they failed to settle the difficult problem.
| A．Lack in | B．Lacking of | C．Lacking | D．Having lacked |