Current cancer treatment depends on drugs and hormones(chemotherapy)，surgery，radiation therapy，or a combination of these．The earlier cancer is diagnosed and the sooner treatment can be implemented，the greater the chances of a successful cure．The poor success rates in treating lun9， breast，and colorectal tumours are due mainly to lateness of diagnosis of many of these tumours．
All forms of treatment have disadvantages．Most chemotherapeutic drugs are designed to attack the genetic material--the DNA—of the tumour ceils in an effort to stop them from multiplying and spreading the tumour．But these drugs are not specific and can also kill normal healthy cells．In radiation therapy， radiation directed at the cancer may destroy normal tissue in adjacent areas．Improvements in equipment and radiation sources，however，have been able to reduce this risk．
If the tumour is confined to a distinct area，such as a portion of the colon or lun9，it may be possible to remove it surgically’ but the malignant cells must be completely removed in order to reduce significantly the risk of developing metastases(secondary tumours)through the migration of cancer cells． Cancer of the breast，for example，tends to metastasize to the bones，while melanoma tends to sDread to the Iun9·Once a tumour has metastasized to diffuse areas of the body，it is much more difficuIt to remove the secondary tumours surgically；they may be numerous and inaccessible，and chemotherapy may be the only option．
some of the greatest successes in treating cancer have occurred with the rarer tumours．Platinum— based drugs are proving effective against cancers of the ovaries and testes， for instance．Drugs and radlotheraPY have done much to prolong survival in those with cancer of the lymphoid tissue，where the body’s defense cells are found． And transplantation of bone marrow cells is reducing the dearh t011 from childhood leukemias．The Success of this technique depends on matching the donor marrow cells to those of the reclDlP ent to prevent rej ection and on knocking out the parts of the donor marrow that will attack their flew host．①
An estlmated one in three persons in developed countries will get cancer at some point in his life． Until more effective treatment of the common tumours can be developed， success in overcoming cancer will depend on early diagnosis of the disease and avoidance of known environmental carcinogens such as clgarette smoke’ some industrial chemicals，and possibly the rich，fatty，low-fibre foods of modern diets．[409 words]
1．Which of the following statements is TRUE according to this text?
A．It is possible to cure some cancers before more effective cancer treatment can be developed．
B．All forms of cancer treatment have disadvantages except radiation therapy．
C．The chances of successfully curing cancer are greater in developing countries than in developed ones．
D．The more developed a country is，the higher the rate of its people who will get cancer．
2．The 3rd paragraph is mainly about______．
A．secondary tumours
B．the migration of cancer ceIIs
C．surgery in cancer treatment
D．the advantages of chemotherapy
3．According to this passage，______．
A．the migration of cancer cells contributes to the development of metastases
B．chemotherapy contributes to the success of removing secondary tumours surgically
C．breast cancer tends to invade the lung
D．melanoma tends to invade the bones
4．The author believes that______．
A．surgery is the best treatment of cancer currently
B．no cancers cannot be overcome if diagnosed early
C．none of the current treatments of cancer is perfect
D．the most effective treatment of cancer will be developed SOOner Or later
5．______may be responsible for the development of cancer．
A．Early diagnosis of the disease
B．Environmental carcinogens
C．Platinum-based drugs
D．Childhood leukemia
All forms of treatment have disadvantages．Most chemotherapeutic drugs are designed to attack the genetic material--the DNA—of the tumour ceils in an effort to stop them from multiplying and spreading the tumour．But these drugs are not specific and can also kill normal healthy cells．In radiation therapy， radiation directed at the cancer may destroy normal tissue in adjacent areas．Improvements in equipment and radiation sources，however，have been able to reduce this risk．
If the tumour is confined to a distinct area，such as a portion of the colon or lun9，it may be possible to remove it surgically’ but the malignant cells must be completely removed in order to reduce significantly the risk of developing metastases(secondary tumours)through the migration of cancer cells． Cancer of the breast，for example，tends to metastasize to the bones，while melanoma tends to sDread to the Iun9·Once a tumour has metastasized to diffuse areas of the body，it is much more difficuIt to remove the secondary tumours surgically；they may be numerous and inaccessible，and chemotherapy may be the only option．
some of the greatest successes in treating cancer have occurred with the rarer tumours．Platinum— based drugs are proving effective against cancers of the ovaries and testes， for instance．Drugs and radlotheraPY have done much to prolong survival in those with cancer of the lymphoid tissue，where the body’s defense cells are found． And transplantation of bone marrow cells is reducing the dearh t011 from childhood leukemias．The Success of this technique depends on matching the donor marrow cells to those of the reclDlP ent to prevent rej ection and on knocking out the parts of the donor marrow that will attack their flew host．①
An estlmated one in three persons in developed countries will get cancer at some point in his life． Until more effective treatment of the common tumours can be developed， success in overcoming cancer will depend on early diagnosis of the disease and avoidance of known environmental carcinogens such as clgarette smoke’ some industrial chemicals，and possibly the rich，fatty，low-fibre foods of modern diets．[409 words]
1．Which of the following statements is TRUE according to this text?
A．It is possible to cure some cancers before more effective cancer treatment can be developed．
B．All forms of cancer treatment have disadvantages except radiation therapy．
C．The chances of successfully curing cancer are greater in developing countries than in developed ones．
D．The more developed a country is，the higher the rate of its people who will get cancer．
2．The 3rd paragraph is mainly about______．
A．secondary tumours
B．the migration of cancer ceIIs
C．surgery in cancer treatment
D．the advantages of chemotherapy
3．According to this passage，______．
A．the migration of cancer cells contributes to the development of metastases
B．chemotherapy contributes to the success of removing secondary tumours surgically
C．breast cancer tends to invade the lung
D．melanoma tends to invade the bones
4．The author believes that______．
A．surgery is the best treatment of cancer currently
B．no cancers cannot be overcome if diagnosed early
C．none of the current treatments of cancer is perfect
D．the most effective treatment of cancer will be developed SOOner Or later
5．______may be responsible for the development of cancer．
A．Early diagnosis of the disease
B．Environmental carcinogens
C．Platinum-based drugs
D．Childhood leukemia