题目内容：

阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。

We’ve all heard about the power of positive thinking, but a recent study found that people who think they’re getting fit actually get more positive benefits from activity, according to a Reuters Health article.

  The study examined hotel housekeepers over a period of four weeks. Some of the housekeepers were told that their work duties gave them enough activity to meet the Surgeon General’s health guidelines (准则). Another group of housekeepers were told nothing. After four weeks, the housekeepers who believed their work activity counted as exercise lost weight and body fat, and their blood pressure went down.

   The results of this study suggest that it’s important to understand and believe in the positive benefits of your activity. So here are a few things to think about the next time you exercise:

  Just thirty minutes of quick walking each day can greatly reduce your risk of a heart attack. Even your housework ― like yard work and house cleaning ― can help you burn calories and increase your fitness levels.

  Weight bearing activity just a few times a week can build bone density (密度) and reduce your chances of developing osteoporosis (骨质疏松).

  Three 10-minute workouts（锻炼） throughout the day are just as good to your health as one long workout.

  Moderate (适度的) amounts of exercise have been linked to lower rates of heart disease, stroke and even cancer.

Strength training can help make daily activities like carrying bags or laundry feel easier.

Regular exercise will reduce stress, keep you in a good mood and improve the quality of your sleep.

1.The main purpose of this passage is to _____.

A. encourage people to think they will get fit in different activities

B. tell people how to finish the work duties better

C. tell people how to lose weight

D. advise people to do more housework

2.It can be inferred from the passage that _____.

A.  thought is more important than activity

B. housekeepers lead a happier life than workers

C. positive thinking does good to our health

D. if one wants to get fit, think more

3.The housekeepers who were told their work would keep them fit _____.

A. found it hard to finish their work on time   

B.  lost weight and enjoyed better health

C.  had little sense of humor     

D. gained weight after the work

4.Which of the following is NOT the suggested things to think about when you exercise?

A. Housework helps burn calories.

B. Regular exercise leads to better sleep.

C. Weight bearing activity does good to people.

D. Walking a dog reduces the chance of a heart disease.