题干
Wild animals are our friends. We shouldn't kill them food or clothing.
A：in
B：with
C：about
D：for
答案(点此获取答案解析）
D
Wild animals are our friends. We shouldn't kill them food or clothing.
A：in
B：with
C：about
D：for
鲁宾和卡门利用某种植物，采用同位素标记法进行了如下两组实验：