题目

阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。 Surfing the Internet for fun will make you a better employee, according to an Australian study. The University of Melbourne study shows that people who use the Internet for their own reasons at work are about 9 percent more productive(具有创造性的) than those who do not. Study author Brent Coker said, “Surfing the Internet at times helps increase workers' attention.” “People need to relax for a bit to get back their attention,” Coker said on the university's website. “Having a shor用化学符号表示:（1） 3个氢分子____________________________；（2）空气中含量最多的元素____________________________；（3）氯化钠中的阴离子____________________________；（4）儿童缺____________________________；会导致骨骼畸形（5）黄铜中含有铜和____________________________；（6）氯化铁中铁的化合价 ____________________________；