【業精於勤，事立於豫】評論

Many doctors and scientists believe that there are different causes for the different forms of cancer. Working conditions may __51__ cancer. For example, people who work in __52__ contact with chemical compounds like arsenic(砷) or asbestos(石棉) may develop cancer. People who work for long periods of time with X-rays or radioactive material may get leukemia or cancer of the skin, bone or lungs. Smoking is __53__ cause of cancer. Many experiments have shown that smoking can produce lung cancer as well as cancer of the mouth, larynx and esophagus. __54__, viruses may cause cancer. S...

【失敗不是世界末日，放棄才是】評論

題目少了句號和逗點..... 怪不得我看了半天@@建議修正一下題目，感謝Many experiments have shown that smoking can produce lung cancer as well as cancer of the mouth, larynx and esophagus 54 viruses may cause cancer.