—What are you mailing, Ryan?—A textbook __________ a new method of teaching physics. I want my friends to take a look at it.
. He is too tired ________ any longer.
What do you think “anxious” ______?
This book ______ Tom’s father’s, because his name is on the book.
This question is ______ easy, all the students can answer the question.
I don’t know _________.