You will succeed in the end ____ you give up halfway．

The process of producing electricity may also give out CO2, ______ you heat your house with electricity instead of charcoal.

_________you have expressed your fierce determination to get it right, you should act immediately.

He failed in the exam not only        his laziness but also        he didn’t listen to the teacher.

You shall get a film ticket free _______ you use your credit card twice this month.

High school students should be given enough sleeping time , _______ they are busy with their study .

    Professor Hawking stepped into the office I knew that there was no hope.

—Do you think the weather will be all right this summer?
—No, _____ we are lucky. The newspaper says it'll be very hot anyway.

_______________made our school proud in 2011 was ____________ more than 40% of the  students had been admitted to key universities.

____time goes by, Mother’s hair is turning gray and the wrinkles on her face deeper.