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.

A 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.

答案解析

46 A 文章第一(yi)段提(ti)到，我們都曾(ceng)感覺過疼痛。從空(kong)格前一(yi)句(ju)的內(nei)容，即(ji)“有些人很少遭受疼痛之苦”，可以推斷空(kong)格處(chu)句(ju)子的內(nei)容應當(dang)與這一(yi)句(ju)的內(nei)容相反，即(ji)“另外一(yi)些人卻總是遭受疼痛的襲擊”。

47 C 空格(ge)前的(de)句子(zi)講到，疼痛是(shi)我們身體(ti)的(de)警(jing)報系(xi)統。因此接(jie)下來的(de)句子(zi)應(ying)該(gai)說(shuo)明這(zhe)樣說(shuo)的(de)原因。

48 D 空(kong)格后一句(ju)講到，然而，有(you)關疼痛(tong)過程的新知識使醫(yi)生得以更好地控(kong)制疼痛(tong)。由此可見，空(kong)格處句(ju)子(zi)的內容(rong)應與此句(ju)內容(rong)相反(fan)，即醫(yi)生對(dui)疼痛(tong)過程了解(jie)得很(hen)少。

49 B 空(kong)格前(qian)一(yi)句中(zhong)的“chemical and electrical signals”等詞語是對(dui)空(kong)格處句子的很好提示。

50 E 文章第四段最后一句提到了“two different kinds of pain messages”，而文章最后一段第一句中又用了“The first message”，顯然，空格處的句子應以“The other message”開始。