Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.

Mobile phones emit microwave radio emissions. Researchers are questioning whether exposure to these radio waves might (33) _______ to brain cancer. So far, the data are not conclusive. The scientific evidence does not enable us to say with certainly that mobile phones are categorically (34) _______. On the other hand, current research has not yet proved clear adverse effect associated with the prolonged use of mobile phones.

Numerous studies are now going (35) _______ in various countries. Some of the results are contradictory but others have shown an association between mobile phone use and cancer. (36) _______, these studies are preliminary and the issue needs further, long-term investigation.

Until the scientific data is more definite, it is prudent for people to try not to use mobile phone for long periods of time. Don’t think that hands free phones are any safer either. At the moment, research is in fact showing the opposite and they may be just as dangerous. It is also thought that young people (37) _______ bodies are still growing may be at particular risk.

Điền vào ô trống 36

A. Additionally

B. However

C. While

D. Though

Trường hợp nào sau đây khi phản ứng xảy ra hoàn toàn thì thu được kết tủa? 

A. Cho 1 lượng dư NaOH vào dung dịch AlCl₃. 

B. Cho lượng dư AlCl₃ vào dung dịch NaOH.

C. Cho từ từ HCl vào dung dịch NaAlO₂ cho đến dư

D. Cho 1 lượng NaAlO₂ vào lượng dư H₂SO₄