河里游动的虾，树上鸣唱的知了，都属于节肢动物的理由是 [ ]

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问题选择题

A．能迅速避开敌害　　

B．体表有外骨骼，足和触角分节

C．都用气管进行呼吸

D．都有三对足，两对翅

答案

答案：B

填空题

软熔带位置低，则上部气相还原的块状带较大有助于煤气利用的改善和（）降低。

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单项选择题

The major goal of physical education programs in schools is to help all children become physically fit. But only a small proportion of children ever participate in team sports. Moreover, team sports usually do less to encourage fitness in participants than do physical education programs that focus directly on aerobic exercise.
The considerations above, if true, could be used most effectively to argue against

A．the use of in-school physical education programs to encourage lifelong fitness habits in students.

B．the participation by young children in community sports teams.

C．schools’ relying heavily on aerobic exercise programs to help all children become physically fit.

D．the use of a large part of a school’s physical education curriculum for team sports.

E．(E) the use of team sports in schools as an occasional activity for talented athletes.

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