_____ do you talk to your teacher at the School of the Air?—Once a week.[ ]

You can never imagine what great difficulty I have ________ your house.

Would you like to go and see Avatar with me tonight? — Thank you very much , but I it already.

There are ________ of students in our school, but only ______ are girls.

People say your little brother has been admitted into QinghuaUniversity.—Yes. Never ________ he could achieve so much success.