Climbing Mount Tai great skills and not without risk.
| A．requires; is | B．required; was | C．required; are | D．required; were |
This word is wrongly spelt；a letter is _______.
| A．left behind | B．left alone | C．left out | D．left off |
It makes _______ big difference to keep calm when giving _______ first aid.
| A．a, / | B．/, the | C．a, the | D．/,a |
_______, the experiment will be successful.
| A．If carefully doing | B．If it done carefully |
| C．If carefully done | D．If doing carefully |
In the front of the hall _______ a group of pupils, who were listening to the lecture attentively.
| A．were sitting | B．sat | C．sit | D．was sitting |
Have you ever had a case _______ someone accused your journalists of getting the wrong end of the stick?
| A．where | B．which | C．that | D．when |