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【单选题】
What did the researchers find in their study of female zebra finches?A.
Female finches liked songs male finches sang for them.
B.
Female finches only liked songs male finches sang for their mates.
C.
Female finches liked to listen to songs from both speakers.
D.
Female finches chose the best male singers as their mates.
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举一反三
【简答题】A．The man, his wife and his daughter. B．The man and his wife. C．The man's wife and his two children. D．The man, his wife and his two children.
【单选题】切削用量三要素对刀具耐用度的影响程度为
A.
背吃刀量最大,进给量次之,切削速度最小
B.
进给量最大,背吃刀量次之,切削速度最小
C.
切削速度最大,进给量次之,背吃刀量最小
D.
切削速度最大,背吃刀量次之,进给量最小
【单选题】— His sudden death surprised his wife. — It was so bad. His wife was surprised ____ his death. [ ]
A.
by
B.
with
C.
at
D.
on
【单选题】双曲柄机构机架长度为50mm,两连杆长度分别为100mm和150mm,则连杆长度L的取值范围是()。
A.
50mm≤L≤150mm
B.
100mm≤L≤150mm
C.
150mm≤L≤200mm
D.
100mm≤L≤200mm
【单选题】确定双曲柄机构机架长度为50mm,两连架杆长度分别为150mm和100mm,这连杆长度L的取值范围是__。
A.
50mm≤L≤150mm
B.
100mm≤L≤150mm
C.
150mm≤L≤200mm
D.
100mm≤L≤200mm
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