【判断题】按钮的复合触点在按下按钮时的动作为常闭触点先断开,常开触点后闭合。
【简答题】The superstars debuted in late 1980s including ______.
【单选题】Why did saccharin have a bad name in the late 1970s and early 1980s?
A.
Because saccharin contains no calories.
B.
Because some people developed cancer after taking saccharin.
C.
Because saccharin was reported to have caused cancer in lab animals.
D.
Because saccharin tastes bad.
【判断题】复合按钮按下时,常开触点先闭合,常闭触点后打开。
【判断题】按下复合按钮时先断开常闭触点,然后接通常开触点 ;当 释放复合按钮 后, 先断开常开触点,再接通常闭触点 。
【判断题】按下复合按钮时,常开触点先闭合,常闭触点再断开
【简答题】What was the situation like in late 1980s?
【判断题】按下复合按钮时,常开触点先闭合,常闭触点后断开