| 1. | It seems neither necessary nor credible .
这看来既非必需，也不可信。 |
| 2. | These reference books are necessary to us .
这些参考书是我们所必需的。 |
| 3. | Air and water are indispensable to life .
空气和水是生命所必需的。 |
| 4. | A binder is necessary for strand integrity .
粘结剂对纤维的集束性能是必需的。 |
| 5. | You have to know your costs before you sell .
你卖出东西之前，必需知道你花费的成本。 |
| 6. | Such tilting will be necessary .
这种改变是必需的。 |
| 7. | A various scholar must have various opinions .
一个多方面的学者，必需要有多方面的见解。 |
| 8. | Water is one of the materials required to sustain life .
水是维持生命所必需的物质之一。 |
| 9. | It involves more than twice the necessary exertion .
这使得他们所用的力量是必需的两倍。 |
