Throw (or knock) someone for a loop: to confuse or shock someone, which usually makes the person very upset because he/she doesn’t expect it.

这个常用口语的意思是让某人震惊或困惑，是会让某人生气的震惊或困惑，因为完全处于某人的意料之外。

造句：

1). He threw me for a loop when he said he was quitting his job.

2). He totally threw me for a loop when he decided not to take my advice on the project we have been working on.