When ____ help, one says "Thank you" while when _____ help, one asks "Can I help you?"
Supporters of underground development say that building down ______ building up is a good way to use the earth’s space.
---______ he managed to solve the problem?---Oh,he turned to Professor Lee for advice.
Lucy cut down her daily spending in order to the financial storm.
Steven was playing the violin loudly the whole night.But I wasn’t bothered by his loudness so much as by his lack of ______ .
is obviously right is to give all children equal opportunities to develop their special gift.