89.To save money for my education,my mother often takes on more work _____ good for her.A.than what is\x05B.than that is C.than it is D.than is为什么选b,请细讲,
问题描述：
89.To save money for my education,my mother often takes on more work _____ good for her.
A.than what is\x05B.than that is C.than it is D.than is为什么选b,请细讲,
答
这道题我查了一下网上的资料选D
than作关系代词时,一般用在形式为比较级的复合句中,其结构为形容词比较级（more）．．．than＋从句,than在从句中作主语,相当于that,代表它前面的先行词.than 作关系代词,先行词就是more work,所以就不需要that,it等代词了.
比如：You spent more money than was intended to be spent.
你花的钱超过了预定的数额.（than是关系代词,在句中作主语,其先行词是money）