Stay Fitness Club—the Club with a Difference

Get off the sofa! It's summer! Let's spring into action! We want to help you get fit and stay fit.

Join our fitness club and become a member. Then, you can enjoy our classes for free. You can enroll（注册） for as many classes manage.

We offer classes in:

Yoga

Indoor cycling

Dancing

Taekwondo

Chinese kong fu

We also have fantastic facilities（设施）：

Machines—They use the very latest technology.

Changing room—There are excellent showers and lockers to keep your things safe.

Lounge area—You can relax and enjoy a cooling drink and a healthy snack.

The membership fee（会费）is very low. You can pay weekly or monthly. It is up to you. When you have paid the fee, you can come as often as you want. Our friendly staff（工作人员）will be glad to answer your questions.

Come to Stay Fitness Club. You are never too old or too young to start a fitness programme.

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4.6g某物质与氧气反应，生成8.8g CO₂和5.4g H₂O，下列说法正确的是（　　）

下列说法中是真命题的有（   ）
①一条直线的平行线只有一条；
②过一点与已知直线平行的直线只有一条；
③因为a∥b，c∥b，所以a∥c；
④经过直线外一点有且只有一条直线与已知直线平行。