春秋战国时代，人类改造自然、征服自然的能力在逐步的提高。下列现象不能说明这一现象的是[ ]

A．牛耕的使用

B．铁农具的推广

C．水利的兴修

D．变法的进行

Jane's pale face suggested that she ____ ill, and her parents suggested that she ____ a medical examination. [ ]

A. be; should have　

B. was; have

C. should be; had　　　

D. was; has