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(xiàng)選擇題

If the meter needle of the oxygen indicator cannot be set to zero,what should be done? ()

A.Replace the batteries
B.Check the sampling tube for blockage
C.Adjust the final reading by the amount the needle is displaced from zero
D.Replace the platinum filament

微信掃碼免費(fèi)搜題