At the meeting, the old man ________ some good advice about bringing down the market price of housing.
The telephone rang at midnight, but it stopped ______ I could answer it.
The radiation amount of a mobile phone for two half-hour periods per day is equal to ___ to an X-ray for ten seconds.
If only he _____ to send that letter to my grandpa, my grandpa will come to help me. Look, I’m so helpless now.
______ he realized it was too late to return home.
Several of the off-shore islands are ______ , now that we have a motor boat.