题目

Under good treatment, she is beginning to ______ and soon come back to work.   A. wake up           B. grow up         C. pick up    D. show up 答案：C空气是一种宝贵资源，人类每时每刻都离不开空气．空气成分按体积计，氧气约占（ ）A．78%B．21%C．50%D．1%