To preheat, "preheat," means to heat, in this case, the oven to get it ready to cook something.   预热，“预热”，在这种情况下，意思是加热烤箱，准备做饭。

An oven, "oven," is a place where you put food into it and you close the door, we would call the oven door, so that the food inside will cook. 烤箱，“烤箱”，就是你把食物放进去的地方，你关上门，我们叫作烤箱门，这样就可以烹饪里面的食物。

Usually, we use the verb bake, "bake," when we are using an oven.  通常，使用烤箱时，我们使用“烘烤”这个动词。

So, we cook the food, or we bake the food in the oven. 所以，我们在烤箱里做饭，或者烘烤食物。

Lucy is going to bake a package of cookies - "of ready-made cookies."  露西打算烤一包饼干——“现成的饼干”。

A package is just the container - the bag or the box where the cookies are kept.  包装袋就是容器——存放饼干的袋子或者盒子。

When Lucy says the cookies are ready-made, "ready-made," she means that she doesn't have to prepare them by herself.   当露西说这些饼干是现成的，“现成的，”她的意思是她不必自己准备。

She doesn't have to get out eggs and water and flour, and make the cookies herself.  她不需要拿鸡蛋，水和面粉，自己做饼干。

Instead, she just has to take the cookie out of the package and put it on the pan and put it in the oven and it will cook. 相反，她只需要把饼干从包装袋里拿出来放在烤盘上，放入烤箱，就可以了。