His first book ______ next month is based on a true story of his family.

A．published

B．to be published

C．to publish

D．being published

铅球从运动员手中抛出后做轨迹为抛物线的运动，倘若在空中飞行时，地球的引力突然消失，不计空气阻力，那么铅球此后将(　　)

A．立即停止

B．慢慢停下来

C．仍做曲线运动

D．做匀速直线运动