Every second counts in the exam, _________ means you must make the best use of the time available.
I don't know when he ___. But when he ___ back, I’ll let you know.
Mr. King, manager of a big department store, is about to pay a visit ___ Chian next month.
Could you ___the radio a little? It’s too noisy.
Once ___, it can never be forgotten.
--Has he passed the exam yet? ---No,He ___ it if he had studied harder.