Switzerland refused to_________ the two world wars.
When he made a speech, the gathering ____ thunderous applause.
It’s the gases ___ natural gas and the burning of coal give off ____ add to the overheating of the earth.
The teacher doesn’t believe his reason for being absent from class ___ he was ill, ____mad him sad.
—— Bob has gone to California. —— Oh, can you tell me when he _____?
It’s easy to learn a country’s culture if one is ____ with its language and customs.