was it not和wasn’t之间区别是was it not只能出现在一般疑问句的句首，而wasn’t it只能出现在反义疑问句的句尾。

举例来说明，例句为It was (not) a beautiful day yesterday.改成一般疑问句，Was it not a beautiful day yesterday？改成反义疑问句，It was a beautiful day yesterday，wasn’t it 相信可以从例句中看出两者的区别。