question problem可數嗎

例句：

Lawlessness is a major problem.

違反法律是一個嚴重的'問題。

The problem is well documented.

這個問題有很多依據。

The problem won't just disappear.

這個問題不會就這樣不了了之的。

That's a very hard question.

那是個很難的問題。

He couldn't answer the question.

他沒有能回答那個問題。