题目

在容积固定的4 L密闭容器中进行可逆反应：X（g）+2Y(g)2Z(g)并达到平衡，在此过程中，以Y的浓度改变表示的反应速率v（正）、v（逆）与时间t的关系如右图。则图中阴影部分的面积表示A. X的浓度的减少                B. Y的物质的量的减少 C. Z的浓度的增加                    D. X的物质的量的减少        Here is a question from http：//answers@yahoo corn．       I’ve been invited to a graduation party, but here’s the problem：I don’t know what I’m supposed to bring or if it's necessary for me to bring a gift．                   —Mike    Answers     Lucy：People usually give money，but you could just，take a graduation card．Graduation is a personal accomplishment．It’s nice to be able to give and receive，but it isn’t necessary．       Peter：You can take some pictures at the party and make a remembrance book（纪念册）for your friends I am sure that it is more important that you should be there than give an expensive gift without attending it．       Richard：Go to Trader Joe’s and buy some nice bottles of wine．They have excellent wines at great prices．Take a card and a bottle of wine to the patty．That way you won’t feel bad about showing up at the party with empty hands．       Diana：If you don’t have enough money, then just take a card．Maybe even a dish you make if you can cook will be OK．That would be a special gift because it is made by you and your friends will never forget it． 1．What’s Mike’s problem?        __________________________________________________________________________ 2．How many people suggest that Mike should bring a card to the party?        __________________________________________________________________________ 3．Who thinks it is not necessary for Mike to bring a gift?        __________________________________________________________________________ 4．Peter suggests that Mike should take some pictures to the party, doesn’t he?        __________________________________________________________________________ 5．What do you think Trader Joe’s is?        _______________________________________________________________________