下列措施可以提高燃料燃烧效果的是( ) ①固体燃料粉碎②液体燃料雾化③煤经气化处

题型:选择题

问题:

下列措施可以提高燃料燃烧效果的是(  )

①固体燃料粉碎 ②液体燃料雾化 ③煤经气化处理 ④通入足量的空气.

A.①③

B.①②③

C.①③④

D.全部

考点:燃料和能源(氢能、风能、核能、太阳能等)
题型:选择题
函数f(x)=∫ox(1-cost)dt,当x∈[
π
2
,π]
的最大值为______.
题型:选择题

在二元线性规划问题中,如果问题有可行解,则一定有最优解

题型:选择题

阅读理解。

     It is not unusual at all for teens to answer their parents with one-word answers. "Where are you going?"

"Places." "When will you be back?" "Sometime." "Who will you be with?" "People."

     That means that the days of your children bounding in the front door with the details of their day are over.

They are breaking away from you so that they'll be able to stand on their own as a young adult.

     Some parents feel sad about this loss of their children's closeness. Of course you miss those conversations

and friendly talks. Once your children move out after high school and establish themselves confidently as a

young adult, they'll come back for easy conversations and even ask for advice. But in order to determine who

they are right now they need to separate from you.

     Your job, however, is to keep them safe-and that requires knowing there they are and who they are with.

Let them know clearly that it's not because you want to dominate their life and control them; it's because it's

a safety issue for family members to keep track of one another.

     When they're home and sit down to eat a meal, sit down with them. You need to open up to them about

your life. Tell them of an interesting incident at the office, let them in on a bit of family gossip (闲谈), discuss

a piece of news with them. They are glad that you see them as old enough to be in on a few experiences of

your life. By letting a teen in on your life, they just may let you in of theirs.

1. The underlined word "That" in Paragraph 2 probably refers to "_____". [ ]

A. teens no longer tell parents their detailed information

B. teens don't tell parents where they had been any more

C. parents are impatient to listen to their children

D. parents are occupied by doing their business

2. It can be inferred from the passage that _____. [ ]

A. the generation gap is becoming wider and wider

B. teens quarrel a lot with their parents

C. teens don't want to live with other family members

D. some parents feel distant from their teenage children

3. The author believes that teens' one-word answers show _____.[ ]

A. their awareness of independence

B. their physical and mental changes

C. an unpleasant parent-child relationship

D. their wishes for keeping silent

4. What's the main idea of the last paragraph? [ ]

A. Parents should understand their children.

B. parents should keep their children safe.

C. Parents should open their hearts to their children.

D. Parents should give their children enough freedom.

5. What's the author's purpose in writing the passage? [ ]

A. To give advice

B. To direct teenagers

C. To present findings

D. To comfort parents

题型:选择题

医院实行新的医疗优惠政策,施行后有的人在医院病好了不走,还有的小病不去看,谈谈你对这种现象的看法。

题型:选择题

感谢信和慰问信的格式和写法完全一样。

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