A. when it is hungry
B. before it plays a trick
C. when it starts to play a trick
D. after it has done the trick
[单选题]Research on animal intelligence always makes me wonder just how smart human
[单选题]Research on animal intelligence always makes me wonder just how smart human
[单选题]Research on animal intelligence always makes me wonder just how smart human
[单选题]Research on animal intelligence always makes me wonder just how smart human
[单选题]Research on animal intelligence always makes me wonder just how smart human
[单选题]Research on animal intelligence always makes me wonder just how smart human
[单选题]Research on animal intelligence always makes me wonder just how smart human
[单选题]Research on animal intelligence always makes me wonder just how smart human
[单选题]Research on animal intelligence always makes me wonder just how smart human
[单选题]Research on animal intelligence always makes me wonder just how smart human