It’s quite normal to ten percent of the cost of a building for a period of six months or so, in case faults are found in it.
| A．keep up | B． keep away | C．keep off | D．keep back |
30. Let Harris play with your toys as well, Clare. You must learn to _____.
| A．support | B．care | C．share | D．Spare |
29. New ways _____ to prevent the river _____.
| A．have found out, from polluting |
| B．have found, from being polluted |
| C．have been found out, from being polluted |
| D．have been found, from being polluted |
28. The first thing she did _____ up to her trainer and thanked her.
| A．was go | B．was going | C．and went | D．Go |
27. The boy gathered all his _____ to stand up.
| A．strength | B．power | C．force | D．Energy |
26. We were all waiting for you. You _____ for the seaside by yourself without
leaving a message.
| A．mustn’t leave | B．shouldn’t have left | C．could not have left | D．needn’t leave |