開篇總起 10 secs

? The professor in this lecture illustrates…

? The lecturer gives a detailed explanation about …

? The lecture brings light to…

第一個subtopic＋例子 25秒鐘

The first kind of … is…

The example the professor uses is…

＋例子

第二個subtopic +例子 25秒鐘

To follow that is the second kind of…, the….

The professor then uses the case of …

+例子

60s回答文本長度在160w左右：

10s~20w

25s~60w

25s~60w