常: Ⅰ形容词1.(一般; 普通; 平常) ordinary; common; normal 短语和例子反常 unusual; abnormal; 人情之常 natural and normal; 习以为常 be used [accustomed] to sth.2.(不变的; 经常) constant; invariable 短语和例子冬夏常青 remain green thr
常闭: normal close◇常闭触点 normally closed contact; 常闭阀 normally closed valve; 常闭控制元件 normally closed control element; 常闭选通电路 normal closed gate; 常闭状态 normally off
