单项选择题
A. both sides of the brain are used equally B. the left side is fully developed C. scientists work on it D. the fight side is fully developed
A.possible B.impossible C.good D.bad
A. Colds are always very dangerous. B. Colds are often unpleasant though not dangerous. C. Actually nothing can help get rid of colds. D. The best way to keep colds away is to be healthy.