蒸馏岗位停车清洗时洗液（）。
A、排入7%己水缓冲槽
B、在残液管取样口排净
C、全部从塔顶蒸走
D、送化学污水池
参考答案：A
You really don’t need to buy another computer ________ you have already got one.
A．while
B．before
C．though
D．when
什么是热塑性塑料和热固性塑料？两者在本质上有何区别？
