问题 问答题

内墙瓷砖润砖时间过长或过短为什么不好

答案

参考答案:内墙瓷砖润砖时间过长或过短都不好,都会严重影响施工质量。
如果浸泡时间不足,砖面吸水力较强,抹上灰浆后,灰浆中的水分很快被砖吸走,造成砂浆早期失去,产生粘结困难或空鼓现象。
如果浸泡过长,阴晾不足时,灰浆抹在砖上后,砂浆不能及时凝结,粘结后易产生流坠现象,影响施工进度,而且灰浆与面砖间有水膜隔离层,在砂浆凝固后造成空鼓。所以掌握瓷砖的最佳含水率是保证质量的前提。应根据浸、晾时间、环境、季节、气温等多种复杂的综合因素,比较准确地估计出瓷砖最佳的含水率。

单项选择题
阅读理解

阅读理解C

Robots are smart. With their computer brains, they help people work in dangerous places or do difficult jobs. Some robots do regular jobs. Bobby, the mail carrier, brings mail to a large office building in Washington D.C. He is one of the 250 mail carriers in the United States.

Mr. Leachim, who weighs two hundred pounds and is six feet tall, has some advantages as a teacher. One is that he does not forget details. He knows each child’s name, the parents’ names and what each child knows and needs to know. In addition(另外), he knows each child’s pets and hobbies. Mr. Leachim does not make mistakes. Each child goes and tells him his or her name, then dials an identification number. His computer brain puts the child’s voice and number together. He identifies the child without mistakes. Then he starts the lesson.

Another advantage is that Mr. Leachim is flexible. If children need more time to do their lessons, they can move switches. In this way they can repeat Mr. Leachim’s lesson over and over again. When the children do a good job, he tells them something interesting about their hobbies. At the end of the lesson the children switch Mr. Leachim off.

小题1:The first paragraph of the passage tells us ________.

A.human beings are not as smart as robots

B.robots can help people in many different ways

C.robots will take the place of man to rule the earth

D.we can only use robots to do some regular jobs小题2: Mr. Leachim’s ________ makes him a good teacher.

A.advantages

B.knowledge

C.appearance

D.energy小题3:The word “flexible” in the last paragraph means ________.

A.not strict

B.not hard

C.changeable

D.suitable小题4:Which of the following statements is TRUE according to the passage?

A. There are 250 robot teachers in the United States.

B. Bobby works in a large office building in Washington D.C.

C. Mr. Leachim is run(开动) and controlled by electricity.

D. The lessons taught by Mr. Leachim are given on a TV set.