ATM网络交换节点采用的主要设备是_________。
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All of US have felt pain.We have cut ourselves.We have been burned.Or we have had headaches.Some of us suffer pain rarely pain rarely. ___________ (46) Pain can take complete control of our body and mind,making it impossible to move and even to think.Yet we need pain.Without it,we would not know.1f we have hurt ourselves.It is our body’s warning system. ___________ (47) Pain is the most common reason we go to a doctor It is the most common reason we take medicines.Until recently,however, most doctors knew of only a few drugs that stopped some pains ___________ (48)But new knowledge about the process of pain is helping them to control pain better. Scientists have learned that the sense of pain is made up of both chemical and electrical signals. ___________ (49)Scientists also have learned that the nervous system sends two different kinds of pain messages to the brain:one very fast,the other slow.The first message is the warning signal.It moves at a speed of 30 meters a second.In less than a second,the brain understands that part of the body is hurt and how badly it is injured. ___________ (50)It tells us not to use the injured part until it heals. 50()
And others have painful attacks all the time.
B. These signals travel from nerve cells in the injured area,up the spinal cord(脊髓)to the brain,and back down again.
C. It tells us that We are injured and should do something about it
D. They knew little about the process of pain itself.
E. The other message moves at a speed of only 013~meter a second.
F. And they send the second,slower message of pain to the brain
CSMA/CD采用随机访问和_________技术。
All of US have felt pain.We have cut ourselves.We have been burned.Or we have had headaches.Some of us suffer pain rarely pain rarely. ___________ (46) Pain can take complete control of our body and mind,making it impossible to move and even to think.Yet we need pain.Without it,we would not know.1f we have hurt ourselves.It is our body’s warning system. ___________ (47) Pain is the most common reason we go to a doctor It is the most common reason we take medicines.Until recently,however, most doctors knew of only a few drugs that stopped some pains ___________ (48)But new knowledge about the process of pain is helping them to control pain better. Scientists have learned that the sense of pain is made up of both chemical and electrical signals. ___________ (49)Scientists also have learned that the nervous system sends two different kinds of pain messages to the brain:one very fast,the other slow.The first message is the warning signal.It moves at a speed of 30 meters a second.In less than a second,the brain understands that part of the body is hurt and how badly it is injured. ___________ (50)It tells us not to use the injured part until it heals. 49()
And others have painful attacks all the time.
B. These signals travel from nerve cells in the injured area,up the spinal cord(脊髓)to the brain,and back down again.
C. It tells us that We are injured and should do something about it
D. They knew little about the process of pain itself.
E. The other message moves at a speed of only 013~meter a second.
F. And they send the second,slower message of pain to the brain
What Is Cancer Cancer is actually a group of many related diseases that all have to do with cells.Cells are the very small units that make up all (51) things,including the human body.There are billions of cells (52) each person’s body.Cancer happens when cells that are not normal grow (53) spread very fast.Normal body cells grow and divide and know when to stop growing.Over time,they also die. (54) these normal cells,cancer cells just continue to grow and divide out of control and don’t die.Cancer cells usually group together to form tumors(肿瘤). A growing tumor becomes a lump of cancer cells (55) can destroy the normal cells around the (56) and damage the body’s healthy tissues.This can make someone very (57) Sometimes cancer cells break away from the original tumor and travel to other areas of the (58) where they keep growing and can go on to form new tumors.This is how cancer(59) The spread of a tumor to a new place in the body is(60) metastasis(转移). People with cancer may feel pretty sick at times—but Call usually still do lots of normal things (61) they are very sick,kids and teenagers with cancer may still be able to go to school.They may be tired Or bruise(出现青肿)easily,but they (62) sometimes go to camp,movies,and sleepover(在外过夜的)parties.People with cancer still like the same things they did (63) they got sick. Cancer in kids is rare—but today, many kids who do get cancer go on living normal lives.The number of kids who beat cancer goes(64) every year because of new cancer treatments.So a lot of kids with cancer will some day drive cars,go to college,have careers,and even get (65) and have families of their own. 55()
A. who
B. what
C. where
D. which