问题
选择题
When ____ comes to research into heart disease and the effects on the body, we do not have
adequate substitutes for the use of animals.[ ]
A. that
B. it
C. what
D. this
答案
答案：B
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When ____ comes to research into heart disease and the effects on the body, we do not have
adequate substitutes for the use of animals.[ ]
A. that
B. it
C. what
D. this
答案：B