【问】 To compensate for his unpleasant experiences in hospital，the man drank a little more thanwas good for him. (New Concept English，Book 3，L. 29)
 请问than从句的主语是什么?
 【答】 在这类句子里有时可以把than看作是关系代词，充当句子的主语(请与充当主语的关系代词that和as作比较)：
 1. You spent more money than was intended to be spent. (CGEL)
 你花掉的钱比原计划的要多。
 2. That morning we drank more tea than had been our custom.
 那天早晨我们喝的茶比通常多了一些。
 3. More middle-aged persons suffer from heart trouble than is generallv realized. (Wood)
 患心脏病的中年人比一般所认为的要多。
 4. This is more money than is needed.
 这笔钱比需要的多。
 5. You seem to take keener interest in the subject than has ever been shown before.
 看来你现在对这个科目的兴趣比以前要浓厚得多。
 6. The town offers better cultural advantage than has been generally supposed.
 这座城市所能提供的文化上的优越性比普遍所认为的还要好。
 但是，也有人解释说，在此类句子里，than从句中省略了主语it(即把than看作是连词，而不是关系代词)：
 There were more casualties than was reported.
 →There were more casualties than it was reported there were. (Wood)
 伤亡人数比报导的要多。
 令人遗憾的是，这两种解释之中的任何一种解释都不适用于此类句型中的所有句子。例如，把than看作关系代词的语法学家，不能解释than之前没有中心词的句子以及than从句的谓语动词在数上与中心词不一致的句子：
 1. I don’t think this is any better than was ordered.
 我认为它并不比订的货好。
 2. The really serious cases are fewer than has been suggested. (Wood)
 真正严重的病例比人们推测的要少。
 而把than看作是连词的语法学家则不能解释than从句的谓语动词使用复数的句子：
 He smoked fewer cigarettes than were normally available.
 因此，有的语法学家对此采取了灵活的态度，即有时把than看作是关系代词，有时则看作是连词。例如，R.Quirk等人把下列句子里的than看作是连词：
 Given that this work was produced under particularly difficult circumstances，the result isbetter than could be expected. (CGEL，P. 905)
 由于这件工作是在极其困难的条件下完成的，所以结果比所预料的要好。
 而把下列句子的than看作是关系代词：
 1. He smoked fewer cigarettes than were normally available. (GCE，P. 686)
 2. You spent more money than was intended to be spent. (CGEL，P. 1131)
 并建议读者与下列句子中的than和as进行对比：
 1. You spent the money that was intended.
 2. She is extremely popular among students，as is common knowledge. (CGEL，1116)
 因此看来，你所提到的《新概念英语》中的那个句子最好看作是连词(即省略了主语it)。