单项选择题
A．the difference between boys and girls B．the ability to solve problems C．the development of brains D．the age when babies begin to talk
A．cook B．served C．got D．make
A．50% of the US population forgot to wear safety belt every day. B．The first safety belts in cars appeared forty years ago. C．Safety belts "trap" people in cars that are burning or sinking in water. D．Not wearing safety belts will be fined.