题目内容：

My teacher told me that I must do my homework as______I can.
A.careful as
B.carefully as
C.more careful than
D.more carefully than
我选A.请问为什么?

优质解答

这里关系到careful跟前面词的关系.
careful是形容词,修饰名词; carefully是副词,修饰动词.
句意：老师叫我做作业时一定要尽量仔细.
被修饰词是do,所以要用as carefully as I can.（和我能够一样地小心）
答案C是错的.要选B才对.