(2) 引導(dǎo)非限制性定語從句

在非限制性定語從句中，as作為關(guān)系代詞代替整個(gè)主句，在從句中多作主語，as從句中的系動詞be常常可以省略。as引導(dǎo)的從句位置比較靈活，可以位于主句之前、之中或主句之后。一般用逗號與主句隔開，可譯為“如”、“正如……一樣”、“根據(jù)”、“這”等。如：

* As described above, the laser beam is much more powerful than other light beams.

如上所迷，激光束比其他光束要強(qiáng)烈的多。

* As is noted in the preceding section, two essential elements of any computer are a memory and a processor.

正如前一節(jié)指出的那樣，任何計(jì)算機(jī)的兩個(gè)基本単元是儲存器和處理器。

* Practically, different phases of an alloy act as poles of tiny electrical cells, as do parts of pure metals.

實(shí)際上，合金的不同相起著微型電池兩極的作用，正像純金屬的各部分作用一樣。?

2. 引導(dǎo)時(shí)間狀語從句

作為連接詞，as可以引導(dǎo)時(shí)間狀語從句，在句中的位置比較靈活，譯為“(當(dāng)）…… 時(shí)”、“隨著”等。如：

* As the loop rotates from position A to position B, the conductors are cutting through more and more lines of force until at 90 degrees they are cutting through a maximum number of lines of force.

當(dāng)線圈從A位向B位旋轉(zhuǎn)時(shí)，導(dǎo)線就切割越來越多的磁力線，直到90度時(shí)切割磁力線的數(shù)目最大為止。

* Human leg veins are repeatedly squeezed by the leg muscles as people walk or run.

當(dāng)人走路或跑步時(shí)，人腿靜脈反復(fù)受到腿部肌肉擠壓。