Either mark or his students on the ferry boat. 10. if you want to use the present tense, which word would best fill the blank?

The best word would be were because it is in the past tense :)

It depends on the verb, but you could say "rides," for instance. I think your teacher is trying to see if yo understand that the verb needs to be singular. When we use either/or, we follow it with a singular verb. So you wouldn't say "Either Mark or his students ride on the boat." You would say "Either Mark or his students rides on the boat."

What sisters? is it in a story?