在意思上它们是不一样的,在否定句中既可以用not as ...as...也可以用not so...as,而在肯定句中只能用as...as... He is as clever as you.(He is not as/so clever as you.) 但下面的句子要特别注意:1) I'll come back as soon as possible.2) The clouds are as white as snow.3) He is so strong as to lift a big stone.(so...as to do:那么......以至......)