题目内容

【题目】元素X和Y属于同一个主族。元素X和氢组成的化合物(X显-2价)在通常状况下是一种液体,其中X的质量分数为88.9%;元素X和元素Y可以形成两种化合物。在这两种化合物中,X的质量分数分别为50%和60%,下列说法正确的是( )

A.两种元素分别为C和Si,且酸性:H2CO3>H2SiO3

B.两种元素分别为N和P,且酸性:HNO3>H3PO4

C.两种元素分别为O和S,且酸性:H2SO4>H2SO3

D.两种元素分别是Mg和Ca,且碱性:Ca(OH)2>Mg(OH)2

【答案】C

【解析】根据元素X和氢组成的化合物(X显-2价)在通常状况下是一种液体,可知该元素为O,则元素Y为S。根据非羟基氧原子数越多,酸的酸性越强,可知酸性:H2SO4>H2SO3。

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【题目】B

Montgomery County Special Olympics held its eighth yearly show of unified (联合的)basketball at Blessed Sacrament School. The gym was filled with cheerleaders (啦啦队队员), parents and friends. The walls were covered with posters made by thirdandfourthgraders at the school. And all the elementary, middle and high school unified teams were playing hard and having fun. Every basket, no matter which team scores, is cheered and celebrated.

Special Olympics support more than 20 unified games. What are unified games? They are programs designed for players with special needs. In the games, they play with kids who are volunteers, called unified partners. The special athletes are unable to play normally like other healthy kids, and some of them are wheelchair (轮椅) users. In basketball, the unified partners rebound (抢得篮板球), pass and sometimes push a special athlete’s wheelchair. As Brian Ross, a seventhgrader at St. Albans School in Washington, says, ＂You just try to help and get everyone to take part.＂

Some special athletes have come a long way to be where they are. Caleb Head is a 15yearold special athlete. When he started, Caleb would only stand at the door and watch. Then Caleb began to practice his shooting but still would not play in the games. Now Caleb runs up and down looking for his shot.

The special athletes are not the only ones who benefit (受益) from unified sports; the unified partners do, too. Marla Grusin, whose son Tyler is a special athlete, says every kid should come to a Special Olympics game. If they do, they will learn ＂to share the ball＂ and that the game ＂is not all about me＂.

Not a bad lesson for any athlete.

【1】The first paragraph is about____________.

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B. Special Olympics’ development

C. the benefits of playing basketball

D. an exciting unified basketball game

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A. are disabled

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D. want to become a star player

【3】 According to the text, Brian Ross is most probably____________.

A. a cheerleader B. a special athlete

C. a unified partner D. a basketball teacher

【4】According to Grusin, taking part in Special Olympics games can help children____________.

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那天他借了一本书，书的作者是一名工人。

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