Look at that girl! Is it Susan? –No, it _______ be her. She went to her hometown just now.
There is no doubt the earth is becoming warmer.
I used to go camping a lot, so it isn’t the first time I ____in a tent.
What _______ you do if you _______ 5 million yuan?— I’d travel around the world.
_____ you study math, _____ you’ll be at it.[ ]