It is______ a sharp knife ______I can use it to cut open a hard pumpkin.[ ]

______ will he stay in Beijing?—For a week.[ ]

______ his bike is lost? — He has to go to school on foot.

How do you know so many English words?- _____ reading all kinds of English books , like magazines and newspapers.[ ]

A student _________ from a tree and __________ his right leg.