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举一反三
【单选题】关于弱精子症的定义是（）
A.
a级精子<50％
B.
a级精子<25％
C.
a级精子<15%
D.
a级精子<25%或a级+b级精子<50%
E.
a级+b级精子<50%
【单选题】C With only about 1,000 pandas left in the world, China is desperately trying to clone the animal and save the endangered species. That’s a move similar to what a Texas A&M University researcher h...
A.
essentially new
B.
pioneering
C.
evolutionary
D.
epoch--making