题目内容：

Your brain (大脑) is faster than a supercomputer.

Your cat is in the k____73____. She’s going to step onto a hot oven. You have a very short time to act. When your brain r____74_____ the message coming from your eyes, it quickly calculates when, where and at what speed you will need to stop her. Then it orders your body to move.

Neurons (神经系统) send messages to your brain at more than 150 miles an hour.

A bee lands on your f_____75____. The neurons in your skin send this message to your brain at a speed of more than 150 miles an hour. Your brain then passes the message to your foot to shake the bee off q____76____.

When you learn, you change the structure of your brain.

Riding a bike seems i_____77_____ at first. But soon you learn it. How? As you practice, your brain sends “bike riding” messages along certain pathways (路径) of neurons over and over, forming new connections (关联). In fact, the structure of your brain changes every time you learn. It changes too whenever you have a new t_____78____.

Exercise helps make you s______79____.

It is well known that exercises like r_____80____ or playing basketball are great for your body. Scientists have recently learned that a short time after you’ve exercised, your body produces something that makes your brain more w____81____ to learn. So if you have trouble s_____82____ a math problem, go out and do exercise, then try the problem again. You might d_____83____ that you’re able to solve it.