Listen! There is a knock on the door．Who _____ it be?—It must be Jack．Just now I sent for him．

If it is quite _______to you, I will visit you next Monday.

Who’s the man over there?Is it Mr Black?—-It _____be him.He’s much taller.

I usually sit_____ the classroom, so that I can hear the teacher who likes to stand_____ the class clearly. [ ]

Which city has _____ population, Dongying, Shanghai or Jinan?