A、They present the ways to be more productive. B、They tell us to be more physically healthy. C、They focus on the importance of h

Moderator:
    Hello, ladies and gentlemen. It gives me great pleasure to introduce our speaker for today’s lecture, Dr. David Donald. Dr. Donald, professor of sociology at Washington University,(16)has written numerous articles and books on the issues about how to be more productive, most of which comes from a healthy and positive mindset.
Dr. Donald:
    Thank you for that introduction. I feel happy to meet you here. Are you ready to unlock your productivity potential? Have you accomplished the resolutions you made at the beginning of the year? If you haven’t, don’t worry: here are some tips on how to make your day the most productive.
     (17)The first thing you need to keep in mind is that you are in control of your life.
    Time flies, and sometimes it flies so fast without you realizing it. What you need to remember is that everything in your life is dictated by the choices you make. So, begin each day by reminding yourself that you are in control and you decide what happens today.
    Only you can decide whether or not it is going to be a productive day.
    Start your day with a positive mind. Not all tasks that you have listed are easy. This may include talking to your boss about a raise, tackling a complicated project—or even just going to the gym. You may start thinking that your boss will say "No" or about all the obstacles you are going to face on the project. You might think going to the gym is too tiring and better not do it.
    Abraham Lincoln said, "We can complain because rose bushes have thorns, or rejoice because thorn bushes have roses."
    We just have to look at things differently. Perhaps your boss will consider that you have made valuable contributions to the team and agree that your request for a raise is justified. Look at a complicated project as a challenge that will help you learn something. Think of the benefits going to gym will give you. Learn to be optimistic and good things will follow.(18)On the other hand, if things didn’t go as expected, then always remember: When one door closes, another will open. The lost opportunity may not be for you but you are up for something much better.
    It is all about having the proper mindset. Be positive.
     (19)As human beings, we think that we have all the time in the world to do the things we want and need to do. This is the reason we tend to waste time. We are always thinking that we have tomorrow to spare and we can just push to do things to another day. But what if you don’t have tomorrow?
    Today is something to be thankful for, so better spend it wisely. You’ll never know what is going to happen tomorrow. Do the things that you have set today right at this moment.
    Say "No" to procrastination and always say "Yes" to today.
    That’s all for today’s lecture. Thanks for listening!
16. What does the introduction say about Dr. Donald’s articles and books?
17. What is the first thing to keep in mind according to Dr. Donald?
18. What should we do if something didn’t go as expected?
19. Why do people tend to waste time?