题目内容：

Crossing your legs is an extremely common habit; most people don’t even notice that they’re doing it when they sit down. While you may find it comfortable to sit with one knee crossed over the other, it might be causing health problems that you are not aware of.

A study published in Blood Pressure Monitoring stated that sitting with your legs crossed can increase your blood pressure. The reason this happens is because the blood in your legs has to work against gravity to be pumped back to your heart, crossing one leg over the other increases resistance, making it even harder for the blood to circulate. This causes your body to increase your blood pressure to push the blood back to the heart. You won’t feel any immediate effects, but if you sit for long periods of time it’s important that you take note of how long you have your legs crossed for. You shouldn’t have your legs crossed for more than 15 minutes, and it’s important that you get up and walk around at least once every hour.

Crossing your legs can also lead to neck and back pain. Ideally, it’s best for our bodies to sit with our feet planted flat, hip width apart, on the floor, but it’s not easy to maintain perfect posture all day at the office. When you sit with your legs crossed your hips are in a twisted position, which can cause one of your pelvic bones to rotate. Since your pelvic bone supports your neck and spine, this can cause pressure on your lower and middle back and neck.

You also might notice that when you sit with your legs crossed for long periods of time your feet and legs get tingly or have the feeling of being asleep. This is because when one leg sits on top of the other it causes pressure on the veins and nerves in your legs and feet. It can cause numbness and/or temporary paralysis in the legs, ankles, or feet. While the feeling of discomfort may only last a minute or two, repeatedly crossing your legs until they feel numb can cause permanent nerve damage.

So next time you sit down, try to get yourself in the habit of sitting with both of your feet on the floor. Not only will it help your posture and stability, but it will also save your health in the long run.

1.Why can sitting with your legs crossed increase your blood pressure?

A. Because it stops the blood circulating

B. Because it press the nerves in our legs.

C. Because we will be in a twisted position when we sit legs crossed.

D. Because it prevents the blood in your legs from pumping back to heart.

2.Which kind of health problems will we have if we cross the legs for a long time?

A. our blood pressure will increase.

B. Our neck and back will pain.

C. Our feet and legs may get tingly or have the feeling of being asleep.

D. Both A, B and C.

3.What does the author suggest us do when we sit down?

A. We should walk outside at least once every hour.

B. We need put one leg on the top of the other.

C. We’d better sit with our feet planted flat, hip width apart, on the floor.

D. We should choose the most comfortable way to sit.