—What do you think of the lesson?—This is _____ interesting lesson and it is also _____ useful one.A. an; an B. an; a C. an; the
---Did you have a good time watching the movie last night? ---No. There were two tall boys _______me, and I couldn’t see it clearly.
---What does your brother _______? ---He is of medium height and of medium build.
---Do you like vegetables, Vera? ---Yes. There _______ many kinds of vegetables in the supermarket. I often buy them there.
---Mum, I’m thirsty. I want to have something to drink. ---What about some _______?
I think _______ is really difficult for us to work out this kind of math problem.