制动器的作用是什么？对制动器的基本要求是什么？
参考答案：
作用是：①制动；②顶转子。对制动器的基本要求是：不漏气、不漏油、动作灵活、制动后能正确地回复。
课文句子背诵：写在二卷答题纸相应位置上，写在其他地方该题不得分（共10分）(每空一词)
81. So whether life will continue on the earth for millions of years ①____ _____ will depend on whether this problem can be ② _______.
82.The universe began with a “Big Bang” that threw matter ③_____ ______ ________.
83. She is ④______ a busy life but she says : Once I stop, it all comes ⑤_______ ________ and I remember the chimps in laboratories.
84. ⑥_________ reading made me realize that it was hard work and determination as well as her
⑦_______ ________ that got her into medical school.
85. They went through a ⑧________ province and saw farms that ⑨ _________thousands of acres.
After dinner, they were back in an ⑩_______ area , the busy port city of Thunder Bay at the top of the Great Lakes.
关于ROP的治疗，错误的是( )
A．2区3期病变应行激光或冷冻处理B．出现Plus病变，应行激光或冷冻处理C．5期病变应行玻切术D．4期病变可行巩膜扣带术或玻切术E．出现Plus病变，可临床密切观察
