下列哪项不是雾凇的形成条件?
A. 气温低
B. 水分充足
C. 辐射降温强
D. 风力强劲
If unemplyment contines to rise, social stability may be ___________.
A. dangerous
B. perilous
C. endangered
D. desperate
A patriot thinks first of his country and later of himself.
A. president
B. hero
C. nationalist
D. soldier
A polite person endeavours to please others.
A. civil
B. common
C. prominent
D. hospitable