Look at the wall. There are some pictures ________ it. [ ]
Bob, have you packed yet?-Yes, Mum.-Look over andthat you have taken everything you need.
Who is the tallest boy? —It ______ be John. John is of medium height.
Let’s go ____ a trip to Mountain Huangshan. It’s beautiful. [ ]
It wasproblem thatof the students could work it out.