Carbon dioxide, which makes a ______ between us and the sun, prevents heat from getting out of the atmosphere easily, so the earth is becoming warmer.
--- Mr. Anderson is popular with his students, for he is kind, strict and knowledgeable.--- No wonder he has such a good_________.
--- I hear that Jason is planning to buy a new car.--- I know. By next month, he ________ enough for a used one
It’s illegal for a public official to ask people for gifts or money ________ favors to them.
--- It’s a shame that you missed the lecture on the British culture given by Thompson.--- I _________ it, but I was busy preparing the coming exam.
Readers are required to _________ the rules of the library and mind their manners.