选择题:10. Building that railway was very difficult and i

题目内容:
10. Building that railway was very difficult and involved _____ ten tunnels.
A. dig
B. throwing
C. to have thrown
D. having thrown
参考答案:

关于抗体和免疫球蛋白,以下哪项是正确的A.Ig就是Ab  B.Ig均为Ab,担Ab不一定都是Ig  

关于抗体和免疫球蛋白,以下哪项是正确的A.Ig就是Ab  B.Ig均为Ab,担Ab不一定都是Ig  C.Ig与Ab不同也无关  D.Ig均为Ab,但两者特性不同

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