Expect后面加什么介词

后面加介词for，例如：

1、I had nothing on except for my socks.我除了短袜什么都没穿。

2、The walls were bare except for a clock.墙上除了一只挂钟什么也没有。

3、There was no light except for the occasional glow of a cigarette.除偶尔有香烟的微弱红光外没有一点亮光。