PLC的输出端可以与()直接连接。
A、触点开关
B、接触器
C、行程开关
D、电磁铁
参考答案:B, D
Jack, as well as his friends who ____ football games, ____ traveled with the team.[ ]
A. likes; has
B. like; have
C. like; has
D. likes; have
下列是某兴趣小组根据课本实验设计的一个能说明碳酸钠与碳酸氢钠热稳定性
的套管实验.请观察下图的实验装置、分析实验原理,下列说法错误的是 ( )
A.甲为小苏打,乙为纯碱
B.要证明碳酸氢钠受热能产生水,可在小试管内塞上沾有无水硫酸铜粉末的棉花球
C.整个实验过程中可以看到丙烧杯的澄清石灰水没变浑浊
D.同质量的甲和乙完全反应消耗的同浓度的盐酸体积:甲>乙