--Have you seen Jack? His mother is looking for him all the afternoon.--No, I haven’t. I am sure her mother________be very worried.
–How many students are there in the classroom? --_________.
.Why don’t you________ Beijing duck?
.Look at the hamburger. There’s some chicken ________ two cakes.
These are _______ cups. _______ are over there.
This is _______ armchair. I’m writing with ________armchair.