The doctor recommended that you ________ swim after eating a large meal.[    ]

A. wouldn't  

B. couldn't

C. needn't  

D. shouldn't

破坏了中国自给自足的自然经济基础的是                                 

A．鸦片战争的爆发

B．资本主义萌芽的缓慢发展

C．《南京条约》中的巨额赔款

D．资本主义国家经济势力的侵入