求老师解答：Tom was about to clo

was about to,l,when,my friend tom,go out,came to see me重新组句~

I was about to go out when my friend tom came to see me.我正要出去，这时我的朋友汤姆来看我

C,what Tom was worried about 做整个句子的主语，表示汤姆所担心的事情。就等于The thing that Tom was worried about。
翻译：汤姆所担心的事情全家人都知道。

A