给你50秒钟时间准备朗读。当听到“开始录音”的信号后，立即在80秒钟内朗读短文一遍，
当听到要求“停止录音”的信号时，应立即中止朗读。
(操作说明：学生朗读的准备时间为50秒钟，录音时间为80秒钟。 当80秒钟过后，电脑播出录音中止信号，屏幕即显示第二大题的题目)
Your brain weighs about 1.4 kg. Inside your brain are billions of
cells. Each cell is a thousand times more powerful than a computer! The active
part of your brain is called the grey matter. This part stores information and
gives instructions to the rest of your body.
Most scientists believe
that we only use about 1 per cent of our grey matter. Certain areas of our
brain are not active. The non-active part is called the white matter. It passes
messages within the nervous system. Scientists think that some parts of our
brains can grow stronger if we use them a lot. For example, they found that
parts of a taxi driver’s brain got stronger because he had to memorize all the
streets in a city!
However, if we do not use
our memory regularly, our brains can also get weaker. We need to exercise our
brains just like we need to exercise our bodies!
