.
________ on the subject for half an hour, Liu Ying suddenly stopped.
| A．To be worked | B．To work |
| C．Having worked | D．Having been worked |
He asked us to _______ him in carrying through the plan at the meeting yesterday.
| A．persuade | B．encourage |
| C．assist | D．provide |
Today, we’ll discuss a number of cases _______ parents have much difficulty in communicating with their children.
| A．where | B．as | C．why | D．which |
He failed the mid-term examination and only then _______ how much time he had wasted.
| A．had he realized | B．did he realize |
| C．he had realized | D．he realized |
________confidence and the necessary equipment, they failed to rescue the 42 miners trapped in the coal mine.
| A．Having lacked | B．Lacking of |
| C．Lacking | D．Lack of |
A quarrel _________, which made him ______ his family.
| A．broke down; break out |
| B．broke out; break away from |
| C．was broken away; break down |
| D．was broken out; break away |