Hello to everyone. I have been asked a difficult question by one of my students and I can't find a good answer anywhere.

In the English dictionary that the student showed me, "that" can be dropped sometimes when using a prepatory "it" as the subject of a sentence:

It is amazing (that) you have won the prize.

It is awkward that she should be unable to come.

It is believed that she is kind.

In the first one, "that" is listed as optionally but in the following two it is listed as required. Why? The dictionary is a fairly respectable one here, but I can't vouch for it beyond the fact that it is probably the widest used one in Japan. Thanks.

I know of no rule that might apply in your examples. I would venture to say that if you are a native speaker, you can simply trust your ear as to the omission of that. Dropping it in your last sentence doesn't sound good to my ear since the that clause is so short. However, I have never seen a rule that says it can't be omitted in cases like that.

Any native person's ear will say that that cannot be omitted when it is repeated: It is believed that she is kind, that she always helps the poor and that she often gives money to charity.

Thank you for the reply. I am a native speaker and while I can say something sounds good to my ear or not, for these students, getting something like that wrong on the entrance exams will cause them endless grief and stress. I agree that most of the time it is just "feeling" but when studying for exams where questions like this could come up, I need some sort of systematic say of explaining it. Even something as simple as "for these verbs, you MUST use it, but not for these verbs..." etc.

I know that in other constructions involving "that" there are some rules that I can use to explain it to the students, but this particular construction is leaving me stumped.

Thanks again.