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【单选题】
氨合成时使用铁催化剂,必须将其还原成( )后,才能有催化活性。A.
FeO
B.
Fe3O4
C.
Fe2O3
D.
α-Fe
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皮皮学刷刷变学霸
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【单选题】Why do we call the sun'a life－giving star'?A． Because it gives us warmth．B． Because
A.
25． Why do we call the sun'a life-giving star'? A． Because it gives us warmth．
B.
Because there are some living things on it．
C.
Because plants and animals can't live without it．
D.
Because people have to live in the dark without it．
【单选题】A long-term study of 136 pairs of twins showed that ______.
A.
they lost a little ability to reason over the years
B.
the only factor which declined over the years was their speed with which to perform. mental tasks
C.
their memory was not as good as it had once been
D.
their minds became a bit more active as they grew older
【单选题】The passage states that information can be lost from short-term memory when a person
A.
does not know how to read
B.
repeats the information over and over
C.
processes the information further
D.
is distracted for 20 seconds
【单选题】以下属于As型的鼓室图特点是（）
A.
钟形，峰压出现在-100至+100daPa范围内，声导抗值在0.3~1.6mL
B.
平缓，声导抗值小于0.3mL，在鼓室积液或耵聍栓塞或穿孔时引出
C.
钟形，峰压出现在-100daPa以下，导抗正常，为咽鼓管功能障碍时引出
D.
钟形，峰压在正常范围内，声导抗值大于1.6mL，多见于鼓膜愈合形穿孔
E.
钟形，峰压在正常范围内，声导抗值小于0.3mL，多见于镫骨固定
【单选题】The term 'The 'Lost Generation' mainly refers to the American generation of young people after ______.
A.
WWI
B.
WWII
C.
the Civil War
D.
the Vietnam War
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