阅读短文，从方框中选择适当的句子还原到短文中，使短文意思完整．
Scientists think that many or most animals can't see colors． ．To find out if dogs could see colors，scientists gave dogs food every time they played certain piece of music．   only when they heard this piece of music．They did not get ready to eat when they heard other pieces of music．
Then the scientists gave the dogs food every time they showed them a certain color．The dogs got ready to eat when they saw thi s color．  ．Again the dogs got ready to eat．The colors were al l the same to them．   ，however．For example if  we put food in a red box and do this every day．A monkey wiIi always go to the red box to get the food．   if we then put food in a blue box．