His father happens to be working in your company.
问题描述：
His father happens to be working in your company.
happen to do 是碰巧...但是为什么这里to 后面用的是be 而不是is啊 his father 是第三人称单数 还有就是为什么用 working
答
happen to do 或者happen to be doing 或者 happen to be done.
是三种happen参与的谓语动词的结构.分别是“做”（无明显时间）,“正在做”,“正在被做”