【问】 As it is announced in today’s papers，all the schools will reopen on 1 September.

葛传 教授在《英语惯用法词典》(P.64)中说：“这‘it’是要不得的。”

请问：这‘it’真的是要不得吗?

【答】 准确的说法应当是：这里的it是可有可无的。换言之，这里用it是正确的，不用it也是正确的。

As (it) appears from her essay，she has read widely in Romantic literature. (CGEL)

从她的论文来看，她似乎读了大量的浪漫主义文学作品。

这种含有可有可无的it的as从句常见的还有：

as(it)seems likely，as(it) often happens，as(it) was pointed out，as(it) was said earlier，as I remember (it) ，as I understand(it)(参见 as happens/as it happens)