–Can I borrow your ruler?---Sorry, I left ___ at home. But you can buy ____ in the shop.A. it; one B. it; it C, one; it D. one; one
— ____ do you clean the classroom? — Three times a day.
He prefers _______ to __________.
There _____ an exciting party at Mr. Wang’s this evening.
Are you free now? I have ___________ to tell you.
There is a ______ tree in our school.