单项选择题
A.anticyclone B.cold front C.occluded front D.cyclone
Prior to reading an aneroid barometer，you should tap th...
单项选择题Prior to reading an aneroid barometer，you should tap the face lightly with your finger to（）.
A.expose any loose connections B.demagnetize the metal elements C.bring the pointer to its true position D.contract and expand the glass face
Pressure gradient is a measure of（）.A.a high-pressure a...
单项选择题Pressure gradient is a measure of（）.
A.a high-pressure area B.pressure difference over horizontal distance C.pressure difference over time D.vertical pressure variation
On what does the operation of an aneroid barometer depe...
单项选择题On what does the operation of an aneroid barometer depend?（）
A.Thin，metal，air tight cell B.Curved tube containing alcohol C.Column of mercury supported by atmospheric pressure D.Expansion of mercury in a closed tube
