I admit that the problem is difficult I don’t agree that it cannot be solved.A. As long a

问题补充：

I admit that the problem is difficult, I don’t agree that it cannot be solved.

A. As long as

B. When

C. As

D. While

答案：

A. As long as

B. When

C. As

D. While

解析：选D。考查状语从句。此处while意为“尽管”, 引导让步状语从句, 通常置于句首。