let alone 和survive的用法?

为什么不可以说 He was survived from the fire.

let alone= not to mention ,表示让步 “更不用说”的意思。 给你造个句子你就懂了，  He can even speak French, let alone English.

survive,我们一般用 survive in  这个短语。  随便造个句子，比如  He survived in Wenchuan's earthquake.

http://dict.baidu.com/s?wd=let+alone

http://dict.baidu.com/s?wd=survive