The United States _______ fifty states , one of which is separated from the others by the Pacific Ocean.

The growing speed of a plant is influenced by a number of conditions, _______are beyond our control

How much money does the package cost—It cost 20 yuan ,including two CD-ROMs and a guidebook.

Maria is _____ American girl. She can play_____ chess very well, but she can’t play _____ trumpet.

A number of graduates prefer to work in big cities, where there are a lot of ________ , like convenient transportation, more opportunities and better equipment.