25. Mother told Jim to watch the milk until it boiled and then _____ off the gas.
| A．turn | B．turning | C．turned | D．having turned |
(2012年北京海淀区高三期末)When________if she would request a rise，the actress noted that money was not important.
| A．asked |
| B．being asked |
| C．having asked |
| D．asking |
(2012年重庆联合诊断性考试)It is rather difficult to make friends with him，but his friendship，________，is more true than any other's.
| A．once gained |
| B．when to gain |
| C．after gaining |
| D．while gaining |
(2012年石家庄质量检测)Once ________，such a chance might never come again.
| A．losing |
| B．lost |
| C．to bo lost |
| D．having lost |
(2012年江苏南通九校联考)When ________different cultures，we often pay attention only to the differences without noticing many similarities.
| A．compared |
| B．being compared |
| C．comparing |
| D．having compared |
(2012年潍坊市高三质量检测)A harmonious society is like a symphony or orchestra－
each person contributes a small sound，but when________with other sounds，it becomes beautiful music.
| A．combining |
| B．being combined |
| C．combined |
| D．to be combined |