【简答题】Why do conventional models of the atmosphere fail to predict such a short-lived tornado?
【单选题】What is the fifth paragraph mainly about?
A.
Why people become short-sighted.
B.
Why natural light has a special chemical.
C.
Why playing outside is good for one’s eyesight.
D.
Why daylight is much brighter than indoor light.
【简答题】1森林培育学是研究()和培育森林的理论和技术的科学。
【判断题】两极和高纬度地区气温很低,常常终年积雪形成冰川;而赤道和低纬度地区气温高,根本不可能形成冰川。()
【单选题】The trouble is _____ we are short of hands.