问题 选择题

、H+、H2

A.氢的五种同位素

B.五种氢元素

C.氢的五种同素异形体

D.氢元素的五种不同粒子

答案

答案:D

题目分析:质子数相同,中子数不同的同一种元素的不同核素互称为同位素,由同一种元素形成的不同单质互为同素异形体,因此这五种微粒既不是同位素的关系,也不是同素异形体的关系,而氢元素的五种不同粒子,答案选D。

点评:该题是高考中的常见考点,属于基础性试题的考查,主要是考查学生对有关化学基本概念的熟悉掌握程度,以及灵活运用基础知识解决实际问题的能力。

单项选择题
单项选择题

As a professor at a large American university, there is a phrase that I hear often from students: "I’m only a 1050. "The unlucky students are speaking of the score on the Scholastic Aptitude Test (SAT), which is used to determine whether they will be admitted to the college or university of their choice, or even have a chance to get a higher education at all. The SAT score, whether it is 800, 1100 or 1550, has become the focus at this time of their life.

It is obvious that if students value highly their test scores, then a great amount of their serf-respect is put in the number. Students who perform poorly on the exam are left feeling that it is all over. The low test score, they think, will make it impossible for them to get into a good college. And without a degree from a prestigious university, they fear that many of life’s doors will remain forever closed.

According to a study done in the 1990s, the SAT is only a reliable indicator of a student’s future performance in most cases. Interestingly, it becomes much more accurate when it is set together with other indicators—like a student’s high school grades. Even if standardized tests like the SAT can show a student’s academic proficiency, they will never be able to test things like confidence, efforts and willpower, and are unable to give us the full picture of a student’s potentialities (潜力). This is not to suggest that we should stop using SAT scores in our college admission process. The SAT is an excellent test in many ways, and the score is still a useful means of testing students. However, it should be only one of many methods used.

53 Students’ self-respect is influenced by their ().

A.scores in the SAT

B.achievements in mathematics

C.job opportunities

D.money spent on education