---Is this your ruler?---No, it isn’t. It’s ________.
Mom always tells me that nothing can be learned _______hard work..
_____ excellent work you have done!
— What ____ heavy rain it was! —Yes, but I love _____ air after it rains. It smells so fresh.
--What else must we pay attention to ____ our school clean?--We must not throw any litter onto the ground.
--I think Sam is the strongest student in our class.--I agree with you, but who is the second ____ one?