下述药物中具有中枢镇咳作用的是()
A.氢溴酸右美沙芬
B.马来酸氯苯那敏
C.盐酸伪麻黄碱
D.对乙酰氨基酚
参考答案:A
Chengdu No. 7 High School, _____________ in 1905, is home to a great many excellent students.
A.found
B.founding
C.founded
D.having founded
曲轴上钻有贯穿主轴颈、曲柄和连杆轴颈的油道,其作用是:()
A.润滑正时齿轮
B.润滑连杆轴颈
C.润滑曲柄
D.润滑连杆轴承