If you forget ______ your watch, it is likely to stop soon.

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

Ren Xue’an, a marketing director of CCTV, says that the country’s TV producers need to what is truly valuable.

Millie, here is _____ bridge. What can you see across _____bridge—Oh, _____elephant is standing over there.

The policeman ________ two man fighting in the street. I thought they were drunk.