问题补充:
He was unable to make such progress, .
A. as he tried hard
B. as hard he tried
C. so hard did he try
D. hard as he tried
答案:
A. as he tried hard
B. as hard he tried
C. so hard did he try
(答案→)D. hard as he tried
解析:本题是由as引导的让步状语从句,将表语或状语提前,结构是“表语/状语+as+主语+谓语”。