What is the simple subject in these sentences? I have a quick question. This is really confusing me.

Pls be understood a bit more.

The second sentence, –international and American championship titles–

international title –one title American championship–another title

so both create –titles, two of subjects connected with –And.

So, you need a plural verb—were.

However, what I understand from your question that is you need many morphological matters to understand verb+subject topics.

Pls you should check it out a morphology of grammar book, I mean you need a book that analyses many grammatical matters or you needn’t only a plain grammar book.