Can adverbs modify "that-clause"?

1. She told him only that she loved him.

2. It is just that you don't know what is going to happen.

3. It is only that I understand that you will see it the way that it is meant.

Like in examples 1,2,3 above, can adverbs such as "only", and "just" be modifying "that-clause"?

I think that in example 1, "only" modifies "that she loved him", and in example 2, "just" modifies "that you don't know what is going to happen.