题目

B A(n) (81) ___________writer about 2,000 years ago called Pausanias came on a(n) (82) ___________journey to find out about the present-day Olympic Games. He interviewed a(n) (83) ___________named Li Yan. He learned that there were two main (84) ___________of Games—the Winter and Summer Olympics, and that both were held four years on a regular (85) ___________.Anyone who has reached an agreed standard for their event can be admitted as (86) ___________.To Pausanias’s surprise, women are playing a very important role in many games. Every country wants to (87) ___________the Olympic Games, a1．用化学符号填空：2个氢原子：2H      2个氢气分子2H2      4个钠离子：4Na+2个镁离子：2Mg2+    3个水分子3H2O   4个二氧化硫分子4SO2地壳中最多的金属元素Al    氧化铝中铝的化合价为+3价$\stackrel{+3}{A{l}_{2}}$O3．