单词：come about
发生, 改变方向
come about的用法和样例：
例句
- How did it come about that he knew where we were?他是怎么知道我们在什麽地方的呢？
- Expected or required but not yet having come about.期待发生的被期望或要求但仍未发生的
- How did this come about?这是怎么发生的?
词汇搭配
- come about发生，产生，实现...