Ng-animate不添加ng-enter和ng-leave类

This is my first project working with Angular and i have some troubles with ng-animate. I did a couple of tutorials and in the tutorials i got everything working fine. Now i'm using Angular for a project and i just can't get ng-animate to work properly. The classes such as "ng-enter" and "ng-leave" are not added to the different elements. This is my first project working with Angular a