①Most of us know that exercise is very important．We all need to exercise．Doctors say it is good　②____us．If children often exercise， they are more alert（灵活的）．This means they do better in tests and schoolwork．
    There are many ways to exercise．You can walk， run， swim， skate or play ball games．You should exercise in the following（下面的）ways．
    •You have to like what you're doing．
    •Exercise enough， but not too much．③每周锻炼两次．Thirty minutes each time④____（be）enough．
    •Try all kinds of things until（直到……为止）you find one， two or even three sports right for you．
    Lots of people choose to exercise at fitness centers（健身中心）．Why？ Because there is lots of sports equipment（装备）there．The equipment will help you exercise your arms， legs， and other parts of your body to make you healthy．Some people buy sports equipment for their homes．But it is very expensive．
    Exercising can be fun．Friends can exercise together at a fitness center， or they can play sports together outside．How do you exercise？

（1）把①处画线部分译成汉语

我们中的大部分人知道锻炼是十分重要的．

我们中的大部分人知道锻炼是十分重要的．

（2）在②处填上一个适当的介词

for

for

（3）把③处画线部分译成英语

Exercise twice each week．

Exercise twice each week．

（4）用④处括号中所给词的适当形式填空

is

is

（5）简略回答问题．Why do many people choose to exercise at fitness centers？

Because there is lots of sports equipment there．

Because there is lots of sports equipment there．