题目内容：

Exercise not only improves your appearance，but also improves your health.Health experts advise people to choose physical activities that they find fun.So，what are some of the most popular forms of exercise in the USA?

Walking tops the list.It is considered to be the▲ way to get exercise.Walking is also said to be the least harmful to the knees and feet.So，it's a perfect choice for the old.

Another popular form of exercise is jogging.In the 1970s，Bill Bowerman brought jogging to the USA.He did so after seeing the popularity of the activity during a trip to New Zealand in the 1960s.He started the first jogging club in America.He also helped found Nike.

Swimming is also very popular.It was the second most popular sporting activity in America in 2008.Top activity was walking.When one is swimming，the whole body is put to work.It is said that swimming is good for people with special needs，like pregnant(怀孕的) women.

Dancing can also be a fun way to exercise.This is especially true for those who see exercise as something that they should do.A dance fitness programme called Zumba has grown in popularity in recent years.It was created by Alberto Perez in Colombia in the 1990s.In 2001，he brought the programme to the USA.Since then，it has spread around the world.

1.Which of the following can be put in  ▲  ？

A. easiest    B. most helpful

C. most difficult    D. most expensive

2.Bill Bowerman    .

A. went to New Zealand in the 1970s

B. started New Zealand's first jogging club

C. founded Nike on his own

D. brought jogging to the USA

3.From the fourth paragraph，we can learn that    .

A. swimming was not popular in 2008

B. swimming was more popular than walking in 2008

C. walking was the most popular form of exercise in 2008

D. it's not good for pregnant women to go swimming

4.According to the last paragraph，we know that Zumba    .

A. has a very long history

B. is the name of a dance club

C. was created in the USA

D. became popular not long ago

5.What is the passage mainly about?

A. The advantages of exercise.

B. Some popular forms of exercise in the USA.

C. The history of some forms of exercise.

D. Advice on how to choose the best form of exercise.