按照GB/T13526-92规定，UPVC管材的二氯甲烷浸渍实验，是为了检验管材的塑化程度和均一性。
参考答案：对
2. ---- English, as a living language, ________ all the time.
---- Right. Who knows what it will be like in the years to come?
A．will change
B．is changing
C．was changing
D．has changed
中温固化型的有
