常用结构和句型有：

act as + NP 起…的作用，充当…

be used as + NP (被)用作…

function as + NP 起…的作用

serve as + NP 用作…，充当…

be used for + -ing / NP (被)用来…

be used + to V (被)用来…

serve + to V 用来…

have／ perform the function of + NP 起…的作用，完成…的功能

The function of + NP is + to V …的功用(功能)是…

The powder acts as a catalyst to speed the reaction．

这种粉末起催化剂的作用从而可加快反应。

The storage problem must be solved before sunshine can be used as a source of energy．

在阳光能被用作能源之前，必须解决贮存太阳能的问题。

The commutator thus functions as a switching device ．

这样，换向器可以起一个开关装置的作用。

The superheater serves as a means of raising the steam temperature．

过热器用作提高蒸汽温度的一种手段。

The process of electrolysis is used for the production of very pure specimens of metal．

电解法用来生产很纯的金属样品。

This instrument can be used to measure resistance , voltage , and current .

这仪表可用来测量电阻、电压和电流。

The superheater serves to raise the temperature of the steam .

过热器用来提高蒸气的温度。

The function of an electronic device is to control the movement of electrons .

电子器件的功用是控制电子的运动。

The transistor can perform almost all of the functions of a vacuum tube .

晶体管能完成真空管的几乎一切功能。

责任编辑：admin