Recent studies have discovered that fathers uniquely contribute to the development of their children, _____ in low income families

Where did you see him for the first time?— It was in the factory _________ we worked.

We are sure one day the air in Beijing will be much ______ than today.

I cannot see clearly ________ number of thecar among ________ number of cars

Jose cupped his hands together to cover his mouth ______ other people would see him cry.