* Hydrogen instead of air is frequently used for cooling large turbo generators.

常以氢气代替空气来冷却大型涡轮发电机。

* No longer do the scientists consider the cell merely as a structural unit. Instead they look upon the cell as functional unit of all life.

科学家们不再认为细胞只是ー种结构单位，而把它们看作是整个生命的功能单位。

instead常跟of连用构成insteadof短语，常译为“代替”、“而不是”。

4. just的译法

副词just可以用来修饰形容词、副词、动词和状语从句。汉译时，可根据情况译为“正好”、“刚才”、“正”、“只”、“恰好”等。如：

* We have just discussed how a ballistic galvanometer can be used to measure quantities of electric charge.

我们刚才讨论了怎样可以用冲击检流器来测量电荷的量。

* The motor settles down to a steady speed when it is taking just enough current to produce just enough driving force to work against the load on the motor.

当电动机所用的电流恰好足以产生刚够对电动机所带负载做工的驱动力时，它就会达到并保持稳定的状态。

5. never的译法

never是表示否定的副词，常用来修饰动词。有时never置于句首来加强语气，此时句子倒装。never常常可以译为“绝不”、“从不”、“从来没有”等。如：

* As shown in Fig.8, the resultant current never falls to zero.

如图8所示，合成电流绝不会降至零。

* Still another way to differentiate between centripetal and centrifugal forces is to observe that the two forces are never applied to the same object.

另ー种区分向心力和离心力的方法是，这两种力从不作用于同一物体。