Though the problems were all very hard,K
题型：选择题
问题：
Though the problems were all very hard, Kate kept on working on them she finally solved all of them. [ ]
A. before
B. until
C. when
D. after
题型：选择题
根据家兔和狼的牙齿图解，回答有关问题
(1)写出图中各指示线所指部位的名称并回答：
[1]_________的作用是______________；[2]_________的作用是__________，[3]_________的作用是___________。
(2)_________图是家兔的牙齿，判断的理由是：家兔的牙齿有______________和______________，没有______________，这与______________生活相适应。_________图是狼的牙齿，判断的理由是：______________尖锐锋利，适于______________，这与肉食性生活相适应。