question problem可数吗

　　例句：

　　Lawlessness is a major problem.

　　违反法律是一个严重的`问题。

　　The problem is well documented.

　　这个问题有很多依据。

　　The problem won't just disappear.

　　这个问题不会就这样不了了之的。

　　That's a very hard question.

　　那是个很难的问题。

　　He couldn't answer the question.

　　他没有能回答那个问题。