纺织材料的耐热性及热稳定性
参考答案:
纺织材料的耐热性:纤维经热作用后力学性能的保持性;纺织材料的热稳定性:指纤维在热作用下的结构形态和组成的稳定性。
用所给单词的适当形式完成短文。
I made my first trip to clean the forest that afternoon three years ago.I ___1___(take) a big black
rubbish bag with me. Ten minutes after starting to pick up litter, my bag was filled with cans, bottles,
broken glass
and newspapers.
I ___2___(be) to the forest more than ten times to pick up litter ever since then. I like to be there
and I ___3___(feel) great to do something for the environment.
I can't understand why people drop litter. But I ___4___(keep) picking up litter until they stop
dropping it.
What I ___5___(do) now is only a small bit to help the earth, but I still think it is important.
PVA冷冻机油泵电动机的保护有()保护。
A、过载
B、短路
C、零序
D、欠压