A、Homework must be handed in on time. B、A great deal of equipment is available. C、The students must follow all instructions exac

Before we start our first lab, I’d like to tell you a little bit about the workbook we’ll be using. The first thing I’d like to point out is that the workbook contains a very large amount of material—far more than you could ever handle in a single semester. What you’re supposed to do is to choose the experiments and activities that you want to do, within a certain framework, of course. Part of my job is to help you make your choices.
    Next, I’d like to mention that in each workbook chapter, there are usually two subsections. The first is called Experiments and the second is called Activities. In the Experiments section, the workbook gives full instructions for all the experiments, including alternate procedures. Choose the procedure you wish—there’s plenty of equipment available.
    In the Activities section, you will find suggestions for projects that you can do on your own time. You’ll see that there are usually no detailed instructions for the activities. You’re supposed to do them in your own way.
    If there are no questions, let’s turn to Chapter One now.
Questions 13 to 15 are based on the passage you have just heard.
13. What is the instructor describing?
14. What is the instructor’s main point?
15. How are the Activities different from the Experiments?