桑代克认为学习的实质在于形成______与______之间的联结。
参考答案：情境 反应
已知△ABC与△DEF相似且面积比为9：25，则△ABC与△DEF的相似比为______．
What does the speaker mean().
A.Linda has lost the diamond ring Bill gave her.
B.The diamond is very expensive.
C.The diamond is very small.
