In summer milk will quickly go bad_____ it is put into a fridge.
Although we are young, ______ we can still do something to help them.
It is necessary _____ something to protect our environment.
If it ______ tomorrow, I’ll go hiking with my friends.
I often see her _______ the piano. Listen, can you hear her _________ the piano now?
--- I’m sorry I ____ my homework at home. --- That’s all right. Don’t forget ____ it to school this afternoon.