()indicatesunstableweather.
A. Thepersenceofcirrusclouds
B. Thelow-hangingstratusclouds
C. Thealtocumulusclouds
D. Themassivecumulusclouds
()generallyindicatesthatagaleorstormisapproaching.
A. Fallingbarometricpressure
B. Risingbarometricpressure
C. Thecirculationsofwinds
D. Thechangeofwinddirection
()isasilverycloudinthefrontoffeathersorfibresseenhighupagainstabluesky.
A. Cirrostratus
B. Cirrus
Cirrocmulus
D. Altostratus
()isahighlayerofcloudinthefrontofsmallflakesorcauhflower,whiteincolourwithnodarkshadowsinbetween.
A. Cirrostratus
B. Cirrus
Cirrocumulus
D. Altostratus