problem 
英 [ˈprɒbləm]  美 [ˈprɑbləm] 
n. 难题，困难；逻辑题

例句：
What's the problem? 

怎么回事？

He left home at 16 because of family problems. 

因为家庭问题，他16岁时离开了家。

The main problem is unemployment. 

主要问题是失业问题。

I had no problem recognizing her. 

我一眼就认出了她。

They were having problems with the children. 

他们和孩子相处困难。

The main problem was that I had very little experience. 

主要问题是我没什么经验。