Do you know 2022World Cup will be held in Qatar（卡塔尔）．And FIFA（国际足联） has made a big decision．The 2022Qatar World Cup will be held in November and December．It is the first time FIFA has moved the event from its traditional summer to winter．

    According to the decision，the 2022World Cup will start on November 21．The final will take place on December18，one week ahead of Christmas．The tournament will last 28days，half a week shorter than usual．

    FIFA said，"This is an important step for us．December18，2022is a Sunday，and it's National Day in Qatar，so it fits perfectly．"

    Many people disagree that Qatar has the chance to held the 2022World Cup，since summer temperatures is very high﹣sometimes，the temperature may be about 50℃．So the country has an idea to move it to winter．At last FIFA gave the chance to Qatar．

    Although the change is good for the players，there is still much opposition．The biggest opposition comes from the major European leagues（欧洲联赛），because the new time will be just Europe's club season．FIFA said they will try their best to make things go well．

如图，CD∥EF，∠1=∠2，求证：∠3=∠ACB．

证明：∵CD∥EF，

∴∠DCB=∠2 $\underset{\_}{}$

∵∠1=∠2，∴∠DCB=∠1． $\underset{\_}{}$

∴GD∥CB $\underset{\_}{}$ ．

∴∠3=∠ACB $\underset{\_}{}$ ．

①鼻毛可阻挡吸入的尘埃       

②鼻黏膜分泌的黏液可使吸入的空气变得清洁、湿润

③鼻黏膜内丰富的毛细血管能温暧吸入的空气 

④嗅细胞能接受气味的刺激

1928年，苏联开始实施第一个五年计划，并未受到美国人的关注。4年以后这种情况发生变化，美国出版了大量关于苏联的著作，如《俄罗斯的黎明》《俄国今日：我们从中能学到什么？》。当时，苏联吸引美国人的主要是（    ）