
I have a friend, let's just call him Mr X. He got back his biology papers and found a cross on one of his answers. He doubted the teacher's markings and asked me what is the correct answer.

I took a look at his answer. I said, "Your answer is wrong."
He says, "The question asks in what organ is the sperm found. Isn't it the testis?"

He continued, "Is the spelling wrong? Isn't it
t-e-t-i-s? My answer is right, isn't it?"
I replied calmly, "Erm...no. It's t-e-s-t-i-s for singular and t-e-s-t-e-s for plural.
And he went like this...

"Gosh, I have it but I can't spell it!"