问题
选择题
The fresh air _____ our health and we _____ it.
A．benefits to; benefit
B．benefits; benefit from
C．benefits from; benefit
D．benefits; are benefited by
答案
答案：B
考查动词。句中benefit对……有益；benefit from受益于。句意：新鲜空气对我们健康有益，我们受益于它。
3Z(g)，Z的含量（Z%）随时间t的变化如下图所示。
