as什么情况下 不能放句首

问题描述:

as什么情况下 不能放句首
最好有例句、

相当于although-/ though- 引导让步状语从句时,需要将原来在句子中间或后面的成分提到句首即前置,这时 as-就不会在句首.
Though Tom is a little boy,he can speak several languages.
Little boy as Tom is,he can speak several languages.也就是说当AS 引导让步状语从句时(即表示虽然的意思)就不能放句首了???Sure.