Large ships that travel to the area sometimes have accidents resulting in leaks of gasoline or oil.

VOA: special.2009.06.03

Sometimes not large.

区别不大。

麻省理工公开课 - 媒体、教育、市场课程节选

these are very large places and sometimes you can get lost.

这些地方很大，你有时候会迷路的。

精彩音乐会 - SpeakingMax英语口语达人

And,diseases sometimes kill large numbers of lions.

VOA: special.2009.05.05

Sometimes, sciencecan seem overwhelming. There are complicated concepts, unimaginably large - or small - objects, and vast distances that most people have a hard time understanding.

VOA: standard.2010.05.04