—_______ will your parents take you to Shanghai?

— In about two months, after I finish the final exams.

A．How long

B．How soon

C．How often

D．How many times

如图表示一天之内（早7：00﹣第二天早7：00）温室大棚中CO₂含量的变化，在a点打开通风口的目的是（　　）

A．补充大棚CO₂

B．补充大棚O₂

C．降低大棚温度

D．降低大棚湿度