题目

价格变动通常会引起商品需求量的变化，进而影响商品销售的总收益（总收益=数量×价格）。右图反映的是价格变动对A、B两种商品需求量的影响。以下判断正确的是：       ①A商品可能是生活必需品   ②B商品价格上涨不会导致消费者对其需求量大幅下降   ③A商品价格上涨往往会使A商品销售者总收益增加   ④B商品价格上涨往往会使B商品销售者总收益增加   A．①③      B．②④       C．②③        D．①④       I am taught by many teachers in my school. Every subject has a 1.． (differ)teacher, but I like my math teacher 2.． (well).Her name is Lakshmi but we usually call her Ma’am. She is our class teacher too.Ma’am 3. (join) us last term. She is very kind and her4.of teaching is so interesting and simple that we all can understand what is being taught and how it could be done. Most5.(important), Ma’am teachers math with lots of patience.6. we do not understand a problem, she will spend extra time7.(guide) us until we understand it. And we can go to her at any time during school hours for help.She also helps us with activities at school. When there is some kind of programs, she will be there 8.(help) us to get ready for the show. Even when we go on picnics, she takes good care of9..To me, Ma’am is not only 10.  good teacher, but also our best friend. I love Ma’am and I wish her a happy life.