---Lucy, is maths difficult to learn in a foreign school? ---I’m not sure, but no subject can be learned well __________hard work.
Tom and I _______ good friends . He _______ twelve.
—Is _____ your backpack?--- No, _____ isn’t. It’s ______ backpack.
---Where are my rulers? ----____________
What color is an orange? It’s ______.
There is _____ “u” and _______ “s” in the word “us”.