正常生产期间，吸附剂中注入水的主要部位是（）。
A、抽出液塔
B、成品塔
C、解吸剂再生塔
D、抽余液塔
参考答案：D
Which of the following is right [A] Today is Teacher’s Day. [B] Tomorrow will be Teacher’s Day. [C] Today is not Teacher’s Day.
函数f(x)="sin2x" – cos2x的最小正周期是__________.
