—Whose English book is this?
—It _______ be Lily’s, but I’m not sure.
might
can’t
must
---- It’s very important for everyone to exercise. do you exercise?----Three or four times a week.
---- Is that girl Susan?---- It ______ be her. She left for Beijing yesterday.
----Shall we go to the amusement park this Sunday, mum?---- Sure, ________ I am busy.
This is the third time the famous scientist __________ the United States.
----Philip has gone to New Zealand.----Oh,can you tell me________?