-Can you work out the problem? -I can’t your explain how to do it. A. but for B.

—Can you work out the problem?　 —I can’t ______your explain how to do it.

A. but for 　 B. except C. apart from D. unless

试题答案

A

B，C后不接句子。unless是从属连词，引导条件状语从句。