—They speak perfect English. How long have they learnt it?—_______ they were seven years old.
What will the computer ______ in the future?
Father put the ladder(梯子)_________ the tree to pick the apples for me.
book named Harry Potter is good friend of mine.
--- Would you like to visit the new museum with us this Sunday?--- ________, but I will have to work then.
-- enjoy Beijing opera with us?--- Good idea.