原句：What to do when you know the worst is coming.
这里主句为何没谓语动词呢？
抄句子要抄完整，这哪儿是一个句子？这是小说《哈利波特》中的一段话：
But Harry wasn’t listening. His eyes had fallen on another book, which was among a display on a small table: Death Omens: What to Do When You Know the Worst Is Coming.（但哈利没听。他的目光落在了另一本书上，那是一张小桌子上的陈列品之1、死亡征兆：当你了解最坏的状况马上到来时该如何解决。）红色部分为书名，What to Do When You Know the Worst Is Coming 是该书名的副标题，注意其中的大写字母！
标题常用名词性结构，这是一个疑问句在标题中被压缩成了一个带疑问词的不定式。假如改写成一个句子则为：
What will you do when you know the worst is coming?
