阅读理解。
When we have small cuts in the skin (皮肤), something strange may happen.The cuts are able to heal
(痊愈) themselves in a couple of days. How does this happen? Read on, and you will find out the secret.
Every living thing on the earth is made up of cells (细胞). Cells grow and make new cells. Most cells
are very tiny and we can't see them with our eyes. Different cells have different uses. Our skin cells are
special ones.The cells on the surface (表面) of our skin are old dead cells. New skin cells are right under
the surface. These are the living skin cells. They do work for our bodies. They help protect our bodies
and heal cuts.
Our bodies make skin cells all the time. As the old cells fall off, new cells grow in the same place. Each
person makes about 18 kg of skin cells during his or her life.Surface skin cells fit together closely with no
gapsbetween them. When you cut or bum yourself, you can harm your skin cells. A small cut will not do
much harm. Your skin will quickly heal itself by making new skin cells. How do skin cells work? First, the
cells near the cut get bigger and move into the gap. Next, these bigger cells meet in the middle. They form
a new layer (层) of skin cells. Finally, new cells will grow until the gap disappears completely. In this way,
your skin can grow and get well itself.
How amazing the tiny cells are! Next time you have a cut, don't worry about it.Maybe in a few days, you will be surprised to find it healed.
1. The underlined word "gaps" in the passage means "______" in Chinese.
[ ]
A.突起
B.条纹
C.缝隙
2. From the passage, we know that cells ______.
[ ]
A.are large and we call see them with our eyes
B.can grow and make new cells
C.aren't in most living things
3. Skin cells heal cuts in three steps.______ is the right order.
a b c
[ ]
A.a→b→c
B.b→c→a
C.a→c→b
4. Which of the following is TRUE according to the passage?
[ ]
A.Each person can make 18 kg of skin cells every day.
B.Different cells have different uses in our bodies.
C.The skin cells have little work to do in the body.
5. The best title for this passage should be ______.
[ ]
A.HOW SKIN CELLS HEAL CUTS
B.THE IMPORTANCE OF SKIN
C.HOW TO PROTECT OUR FINGERS