–Look! Someone is cutting a tree on the moon.–It _______ be true, Granny. Our teacher says there is no air there.
Our English teacher often asks us_________ English _____in class.
I’m sorry I’m late again________ the heavy rain.
If it_________ tomorrow, I’ll go birdwatching with my father. -----That’s a good idea.
Not everyone knows_____they want to be.
Science is _____ difficult for some students ____ learn, so many of them don’t like it.