下列实验操作中，错误的是[ ]
A．吸取液体
B．铁丝在氧气中燃烧
C．加热试管中的液体
D．称取同体NaOH
答案：D
—What do you think of the two students ________ to take part in the competition?
—They are hardworking as well as intelligent.
A．selecting
B．selected
C．having selected
D．to select
（）和时间长短的变化情况称为火候。
A、程度高低
B、火光颜色
C、火力大小
D、火焰高低
