Doctors have tentatively concluded that cellphones may ________

* Hướng dẫn giải

Đáp án là B

Ý trong bài: "In one case, a traveling salesman had to retire at young age because of serious memory loss. He couldn't remember even simple tasks. He would often forget the name of his own son. This man used to talk on his mobile phone for about six hours a day, every day of his working week, for a couple of years. His family doctor blamed his mobile phone use, but his employer's doctor didn't agree." Như vậy việc dùng điện thoại di động có thể gây ảnh hưởng đến các chức năng về mặt thần kinh. Đáp án của câu là cause some mental malfunction.