Emergency line operators must always _____ calm and make sure that they get all the information they need to send help.
Stop! You can never touch this machine when it ________, it is very dangerous.
. I think that this film is _______ a film, it is also a good material for education.
I don’t want to read all these old newspapers, please tell me where the __ ones are.
---- How did her family feel when you visited them? ---- My coming ________ the happiness of her family.
_________ to 100℃, water will boil.