As a verb, shudder means to shake and shiver. Being really cold or seeing something that scares you — a ghost! — can make you shudder.

作为动词，shudder的意思是抖动和颤抖。真的很冷，或者看到什么能吓到你的东西，比方说鬼，会让你shudder。

said when you are worried about something unpleasant that might happen or might have happened

我一想到…就惴惴不安，我真不敢想

I shudder to think what my parents will say when I tell them I've failed my exams.

我真不敢想告诉父母自己没有通过考试他们会怎么说。