99色精品-9色在线-99色在线-99色视频 国产欧美日产一区二区三区_亚洲精品亚洲人成在线观看_四虎在线精品永久观看_免费一级a一片久久精

單項選擇題

An accidental path of low resistance, allowing passage of abnormal amount of current is known as a/an().

A.open circuit
B.short circuit
C.polarized ground
D.ground reference point

微信掃碼免費搜題