---Lin Too, open _______door, please. ---I’ m coming, Mum.
You should study harder______ it is too late to catch up.
Tell the boy the news. He is ______to understand it.
Class is over. Let’s stop______ a rest.
--- _________ difference the day made! We were very happy.
--- I didn’t bring back anything from America. --- _________ at all? Why not?