亚马孙雨林对全球水循环和水平衡的作用，主要表现在(　　)

A．通过光合作用放出氧气

B．起着类似海绵的作用，滞蓄大量降水

C．亚马孙雨林所涵养的水量约占地表淡水总量的50%

D．亚马孙雨林的降水量绝大部分是自身产生的

Had she _____ her promise, she would have made it to Yale University. [ ]

A. looked up to

B. lived up to

C. kept up with

D. come up with