下表是大熊猫等种动物的抗体抗原反应:
据此你分析,大熊猫与哪一种动物的亲缘关系最远()
A.小熊猫
B.黑熊
C.马来熊
D.无法确定
参考答案:A
After he retired from the office, Tom ______ painting for a while, but soon lost interest.
A.took up
B.saved up
C.kept up
D.drew up
正常视网膜的动、静脉管径的比例是
A.5:6
B.4:5
C.2:3
D.3:4
E.1:2