As before, he remained unmoved. as是连词还是关系副词？

问题描述

As before, he remained unmoved.  as是连词还是关系副词,介词？

老师答疑

刘老师：

as before 的用法，分两种情况。

1. 用于比较时，as是从属连词，引导比较从句。as before实际省略了前文重复的成分。例如：

I haven't as much responsibility as before.  我不再担负过去那样多的责任了。

Doing business is not as easy as before.  生意不像以前那样好做了。

2. 单独使用时，as是介词，before具有名词的用法。例如：

My garden wants your care, as before. 同先前一样,我的花园仍然需要你去照管。

They don't sing and talk as before.  他们不像以往那样唱歌和说话了。

你的句子属于这一种。

其他类似的表达：

As always he was late and had to run to catch the bus. 他像平时一样又晚了，得跑著去赶公共汽车了。

As usual, there weren't many people at the meeting. 像往常一样，来开会的人不多。

As yet ,no man has set foot on Mars. 直到目前为止，尚没有人登上火星。