It’s nearly eight o’clock. I must hang up and get down to work. My boss________ be here at any moment.

My sister met him at the street yesterday afternoon, so he __________ your lecture.

—When I first got to Harvard, my awkward English brought me great trouble.——Oh, dear, it _______a struggle for you to keep up with other students.

It             be the vocabulary that caused you the problem in the exercise because you know a lot of words.

— Dad, must we wait until the light becomes green? — Yes, I’m afraid we ______. That’s the traffic rule.