齿轮油泵为什么有时吸不上油?
参考答案:
(1)油位不足;
(2)油管路泄漏;
(3)油泵的泵体与泵盖之间密封不好;
(4)油泵零件严重磨损;
(5)吸油网被堵塞。
13 ._______, he is famous for writing blogs.
A. As he is a teacher
B. A teacher as he is
C. A teacher although he is
D. teacher as he is
试剂法白酒中总酸的分析步骤:吸取样品50ml于250ml的锥形瓶中,加入()指示剂2滴,以氢氧化钠标准滴定溶液滴至红色,即为其终点。
A、品红
B、酚酞
C、石磊
D、甲基红