关于it is said that
我看到有这两个句型：
it is said that...
it has been said that...
我想问
1.这两个句型有什么区别吗?也就是说 会因时态不同 而使用范围也不同吗?
2.从句的时态有规定吗?我看到的例句从句时态跟主句时态好像没有任何关系啊 ,如：
it is said that this book has been translated into many languages.
It has often been said that life is difficult as it is.
3.有没有it was said that
和 it had been said that 呢 如果有,它们之间有什么区别啊?