先阅读，再作出选择：汽车在行驶过程中，发动机的功率为P，牵引力为F，汽车行驶的速度为v，这三者之间的关系为P=Fv。当汽车爬坡时，驾驶员的操作总是加大油门同时将变速器换为低档。加大油门是使发动机发挥最大的功率，换为低档是为了减慢车速。那么，在爬坡时减慢车速的目的是（　）

Things to do when you are feeling down

    Let's start with a fact. We all have days when we feel down and discouraged.____ Here is a list to help you get back on track.

    Take care of yourself

    This may seem like an obvious thing, but try your best to get a good night s sleep and eat healthy food when you're hungry____Consider setting an earlier bedtime than usual and stick to it. Make some nourishing snacks that you can easily grab instead of sugary junk food. Fresh fruit, a piece of cheese, some cut-up vegetables, homemade soup, they are all quick and easy options to consider.

    ____

    If you are going through a tough time, think about some healthy comforts that will make you feel better. Take a bike or go for a walk in nature. Treat yourself to a lunch at your favorite restaurant. Listen to some good music. Call a friend. Watch a funny movie. Take a nap. Read a good book. The release from stress will add to your level of happiness.

Make an action plan

    Can you identify what's making you unhappy? If so, you have a good chance of changing it____ You don't have to figure out a whole plan to solve your conflicts; simply taking some steps in the right direction will boost your good feeling.

    This, too, shall pass

    What do you say to yourself when you are going through a tough time? Beating yourself up is not helpful!____ Examples are, “It is what it is; let me just accept it and move on.” “All I can do is put one foot in front of the other and keep moving.” “And finally, this, shall pass.”

A. Science shows that both of these things can have a huge positive impact on both your mood and your blood sugar.

B. A lot of researches show that when we intend to be happy, our thoughts and actions follow suit.

C. What action can you take today that will make you feel better and change the pattern?

D. What can you do to pull yourself back from despair?

E. Try saying things that are comforting your heart and mind.

F. Other times, the blues just seem to hit for no reason at all.

G. Find things to comfort yourself.

    One day, at night, a thief tried crawling (爬行) into a farmer couple's house. In the house lived many mice. The woman in the moonlight saw a mouse crawl into the house. “Look! In comes one.” She said to the man in the house. The thief was so frightened that he hurriedly crawled out of the house and said to the one waiting outside, “She found me when I was just in.” But the thief outside didn't believe him, so he said, “Let us two try to crawl into the house together.” At that time two mice happened to crawl into the house, too. The woman saw the mice and shouted, “In come two, catch them!” The two thieves were terribly frightened. The man in the house said, “You saw them come in but where are they? I will catch them tonight” The two thieves started running away at once.

    The two thieves wanted to make it clear whether they had been found or not the night before. The next day they acted as men selling sweet potatoes and came before the house. The man and the woman were working in their fields. The rein (缰绳) broke and the woman came home for a new one. She saw two men selling sweet potatoes and wanted to buy some. She picked out two which looked like mice. At the time the man couldn't wait for her any longer in the fields and he ran back from the fields to hurry her up. The woman showed the sweet potatoes to the man and said, “How they look like the two of last night!” The man said, “I asked you to fetch a rein, why don't you hurry for it?” The two thieves ran away quickly without their sweet potatoes.