问题 问答题

粘木料用的胶是在100℃左右的温度熬化的,温度再高就会熬焦,失去粘性,所以熬胶要用图所示的两层锅,两层锅之间装着水,这样就不会把胶熬焦了.为什么?

答案

答:由于夹层中有水的存在,所以即使炉火持续加热,最多把水加热到沸腾.通常情况下,水的沸点是100℃,沸腾后温度保持不变,可以有效地防止胶被熬焦、失去粘性.

阅读理解

阅读理解。

     Mr. Jones and Mr. Brown worked in the same office. One day Mr. Jones said to Mr. Brown, "We

are going to have a small party at our house next Wednesday evening . Would you and your wife like to

join us?"

     Mr. Brown said, "Thank you very much . That is very kind of you. We are free that evening. I think,

but I will telephone my wife and ask her. Maybe she wants to go somewhere else that evening." So Mr.

Brown went to the other room and telephoned. When he came back, he looked very sorry.

     "What is the matter?" said Mr. Jones. "Did you speak to your wife?"

     "No," answered Mr. Brown, "She wasn't there, my small son answered the telephone. I said to him,"

Is your mother there, David?' and he answered, 'No, she is not in the house,' 'Where is she then?' I asked. 'She is somewhere outside.' 'What is she doing?' 'She is looking for me.'"

1. A small party will be held ______.

A. at David's house

B. at Mr. Brown's house

C. in the office

D. at Mr. Jones' house

2. Mr. Jones asked ______to the party.

A. Mr. Brown

B. Mrs. Brown

C. Mr. and Mrs. Brown

D. all his friends

3. The telephone was ______.

A. in the same office

B. in a room next to the office

C. in the post office

D. near Mr. Jones' house

4. Mr. Brown spoke to ______on the phone .

A. Mrs. Brown

B. Mrs. Jones

C. David

D. David's friend

5. Why was Mrs. Brown looking for David? Because ______.

A. he went out of the house

B. he was answering Father's phone

C. she knew David had lost his way

D. she thought he was playing somewhere outside

判断题