several thousand和several thousands of都对

有读者问一道选择题：

(1)Several_________houses were washed away by floods.

A. thousand　B. thousands of

答案为A，为何不选B? 我遇见过这样的句子：

(2)The seagulls ate up several thousands of locusts in a short while.

你是对的。既可说several thousand，亦可说several thousands of，还可说several thousand of。

2　thousands upon thousands of与thousands and thousands of同义

有读者问： thousands upon thousands of是否与thousands and thousands of同义， 是否可以互换？

是的， upon与and皆意为in addition to， 但前者似乎较为文气。