1） He express himself as satisfied with our work.

satisfied是形容词，这里as是什么词性？什么用法？

【答】as satisfied with our work 是介词短语，充当宾语补足语。

2）You are not so lazy as him.

表比较时，as后面的可以用主格he吗?

【答】可以。You are not so lazy as him.（as 是介词）/ You are not so lazy as he (is).（as 是连词）

第一个问题，as出身连词，现在被看做介词，引导成分作宾补，不过剑桥英语语法认为，作宾补的是as后面的成分，不包括as。

第二个问题，从来都是个争议中的问题，有的看作连词，有个看作介词，比如《Fowler’s Concise Dictionary of Modern English Usage》：A problem arises because these function partly as prepositions and partly as conjunctions, and their roles are not clear-cut. In broad terms when as or than are felt to be prepositions the objective case is used (as lucky as me), and when they are felt to be conjunctions the subjective case is used (as lucky as I, with am understood). Examples: He was as apprehensive as I about our meeting—J. Frame,1985 。 He was eight years older than I—Lord Hailsham, 1990 He seems to be as lonely as me, and to mind it more—David Lodge, 1991 呵呵，看上去很人性化。不过，我觉得还是看作连词为好，我赞同下面说法：The point at issue is whether as in this context is a preposition,like on or after (nobody would write on he or after we); or whether it is a conjunction, with a following verb that has been omitted:as he is,as we are.It is often better to include the verb, since as fat as I may sound too formal, and as fat as me be frowned on, but nobody can object to as fat as I am.It is actually safer to include the verb where the comparison might otherwise be ambiguous. He sees me as often as Mary may mean either.. as he sees Mary or ... as Mary does.所以，你说的可以用主格吗，不仅可以，而且很可以。