它为每一个菜单选项提供事件处理程序。

It provides an event handler for each menu option.

youdao

您需要一个菜单选项，其中只有一个针对该用户名的选择器。

You need a menu option that has just one selector for the user name.

youdao

将会出现一个菜单选项，显示替代的引用；选择它将会跳回到适当的在我们的场景中第二步中的响应。

There will be a menu choice that shows the reference that was substituted; selecting it will jump you back to the appropriate part of the response from the login in the second step of our scenario.

youdao