问题 单项选择题

下列有关生活常识的说法,错误的一项是( )。

A.含氮、磷化合物的生活污水大量排放可使水体富营养化
B.可用大量盐酸清洗除去烧水用的铝壶内壁的水垢
C.劣质装修材料中的甲醛、苯、氡气等对人体有害
D.废旧电池中的汞、镉、铅等重金属盐对土壤和水源会造成污染

答案

参考答案:B

解析: 水垢的主要成分是碳酸钙和氢氧化镁,使用盐酸可以与二者发生化学反应,生成可溶性的盐,从而除去水垢。但盐酸不能过量,因为过量的盐酸会与铝壶发生反应,故B项中使用大量盐酸清洗除去水垢是错误的做法。正确答案为B。

单项选择题
单项选择题

However important we may regard school life to be, there is no denying the fact that children spend more time at home than in the classroom. Therefore, the great influence of parents cannot be ignored or discounted by the teacher. They can become p allies of the school personnel or they can consciously or unconsciously hinder and frustrate curricular objectives.

Administrators have been aware of the need to keep parents informed of the newer methods used in schools. Many principals have conducted workshops explaining such matters as the reading readiness program, manuscript writing and developmental mathematics.

Moreover, the classroom teacher, with the permission of the supervisors, can also play an important role in enlightening parents. The informal tea and the many interviews carried on during the year, as well as new ways of reporting pupils’ progress, can significantly aid in achieving a harmonious interplay between school and home.

To illustrate, suppose that a father has been drilling Junior in arithmetic processes night after night. In a friendly interview, the teacher can help the parent sublimate his natural paternal interest into productive channels. He might be persuaded to let Junior participate in discussing the family budget, buying the food, using a yardstick or measuring cup at home, setting the clock, calculating mileage on a trip and engaging in scores of other activities that have a mathematical basis.

If the father follows the advice, it is reasonable to assume that he will soon realize his son is making satisfactory progress in mathematics, and at the same time, enjoying the work.

Too often, however, teachers’ conferences with parents are devoted to petty accounts of children’s misdemeanors, complaints about laziness and poor work habits, and suggestion for penalties and rewards at home.

What is needed is a more creative approach in which the teacher, as a professional adviser, plants ideas in parents’ minds for the best utilization of the many hours that the child spends out of the classroom. In this way, the school and the home join forces in fostering the fullest development of youngsters’ capacities.

The author does not directly state, but implies that()

A.participation in interesting activities relating to a subject improves one’s achievement in that area

B.too many children are lazy and have poor work habits

C.school principals do more than their share in interpreting the curriculum to the parents

D.teachers should occasionally make home visits to parents