79. There are only five minutes left before the train leaves. You should run _______ .
Don't be rude to your father. Never in his life ___________ that way.
It seems that living green is ___________ easy and affordable. A small step makes a big difference.
We only had $ 100 and that was ___________ to buy a new computer.
—Volunteering is becoming ___________ popular in China. —Yeah, people are now aware that helping others is helping themselves.
John opened the door. There ___________ he had never seen before.