| 1. | These reference books are necessary to us .
这些参考书是我们所必需的。 |
| 2. | Love is necessary to a successful union .
美满的婚姻必定需要爱情。 |
| 3. | It is necessary to delimit the anomaly clearly .
清楚地圈定异常是必要的。 |
| 4. | It is necessary to exterminate the post at the sawmill .
必须端掉锯木厂边的哨所。 |
| 5. | Secondly it is necessary to define the applied load .
其次，需要确定所作用的载荷。 |
| 6. | It is necessary to draw readers'attention to the catalogue .
必须提醒读者去注意目录。 |
| 7. | It is necessary to have special detectors to pick it up .
这需要用专门的探测器来测量。 |
| 8. | It is necessary to put up control experiments as far as possible .
要尽可能进行对照实验。 |
| 9. | It is necessary to maintain surveillance on these meters .
必须对这些仪表保持经常性的监测。 |
| 10. | It is necessary to know what the public perceives of banks .
很有必要知道公众对银行的了解程度。 |
