Câu hỏi:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word for each of the blanks

Mobile phones emit microwave radio emissions. Researchers are questioning whether exposure to these radio waves might (61) _______ to brain cancer. So far, the data are not conclusive. The scientific evidence does not (62) _______ us to say with certainly that mobile phones are categorically (63) _______. On the other hand, current research has not yet (64) _______ clear adverse effect associated with the prolonged use of mobile phones. Numerous studies are now going (65) _______ in various countries. Some of the results are contradictory but others have shown an association between mobile phone use and cancer. (66) _______, these studies are preliminary and the issue needs further, long - term investigation. (67) _______ the scientific data is more definite, it is prudent for people to try not to use mobile phone for long (68) _______ of time. Don't think that hands free phones are any safer either. At the moment, research is in fact showing the (69) _______ and they may be just as dangerous. It is also thought that young people (70) _______ bodies are still growing may be at particular risk.

Researchers are questioning whether exposure to these radio waves might (61) _______ to brain cancer.