In Simple present^x, Sample^x

Sorry to have confused all of you. My statement"I thought *only* simple present was correct, but I thought wrong. I now know that both present tense and past tense are possible" was only referring to the sample sentence given by Jim(a) "My professor said that spiders are (were...

Thank you very much indeed, Jim. That's a great explanation. You cleared all my doubts. Forgive me for thinking out loud as I hope you can correct me if I am still making any mistakes. Firstly, I didn't notice that it was (can only use "was", "is" not possible?) ...