Question

He is so good a student that he always does his exercise as ______ he can. A. careful so B. care

He is so good a student that he always does hisexercise as ______ he can.
A. careful so B. careful as C. more carefully D. carefully as

Answer 1

答案：D. carefully as 副词carefully修饰动词does
as--so没见过这种用法
c/more 前应加much，as ---as不能直接带比较级

Answer 2

选D.
但是你这个句子是不是不太对，前面的第一个so应该用such才对的。
哪里的题目？

追问

这是我们老师给的题，答案是选D，但as不是接adj原形吗

追答

这里并不是这个结构，选这个adj 还是adv要根据它修饰的主体来决定。
这边是修饰前面的does his exercise,所以主体是一个动词组合，表示动作，所以用副词。
另外你老师大约还是要考AS..AS sb can这个结构。
前面的so是错的，你可以去跟老师讨论下。

Answer 3

选A carefule
as 后面要加形容词。