The model essay of the speech varies from place to place. But you can bring reference books in;
First of all, we should read the teaching materials, and those without * should read them carefully.
Generally speaking, there are two types of lectures:
First of all, the school will assign you a text, prepare lessons within the specified time, and then speak. Generally, schools will take some newly added texts in the textbooks, because they are new and difficult to speak.
The second is to let you choose. If this is the case, you are lucky.
In fact, you can call the local recruitment office. Ask them about the scope.
I hope my answer is helpful to you, and I hope it will be adopted!