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
网友回答
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：考查as引导的倒装句。当as放在名词，形容词，副词的后面，句子使用倒装句。本题hard as he tried=Though he tried hard.尽管他很努力了。。。。