问题 判断题

活塞环分为气环和油环,气环的作用是密封汽缸,并将活塞所吸收的热量传入汽缸壁进入冷却系统。油环的作用是将飞溅在缸壁上过多的润滑油刮下,它是活塞散热的主要路径,特别是第一道环,传递全部热量的40%~50%。

答案

参考答案:错

解析:活塞环分为气环和油环,气环的作用是密封汽缸,并将活塞所吸收的热量传入汽缸壁进入冷却系统。它是活塞散热的主要路径,特别是第一道环,传递全部热量的40%~50%。

阅读理解

阅读理解。

                         UK students get more morrung rest

    You  get lost in the forest, and  then  you walk  forward  and  fall  over.

Opening  your eyes, you find yoursclfin a swimming pool full of chocolate.

Just when you're about to enjoy the chocolate,a voice shouls,“CET UP!!"

    This isn't some boot camp(新兵训练营).It's the wake-up call that

every teenager in the UK goes through each morning.  Sleeping late is their

dream, but they have to get up and go to school early in themorning.

    Now,one  school  finally  understands  that asking teenagers to amve at

school at  9:00  a.m. is not just unfair but can also hurt both kids and their

studies.

    The Monkseaton High School in England recently decided to see whether

there was any diffrence  they started their school day one hour later, at 10:00 am instead of'9:00 am.

    The results have been  surprising. Since  the later start, 28 percent fewer

students  have been absent,seven percent fewer have  been late. Best of all,

students get higher test scores. One stude.nt, Emelye Hood, 13, said, "When

I get more sleep,I can focus(集中精力)more on my lessons.”

    In  trying the experiment(试验),the  school  used studies by Oxford

scientist Russell Foster,a neuroscientist(神经系统学专家).He says

that teenagers have different sleep cycles(周期)than adults.Adults are

active and ready for the day at 8:00 am, while teenagers aren't fully awake

until 10:00 am.

    Ryan Thompson, 13, also welcomes the later start. He says, "Now I get

to sleep and don't rush breakfast. It makes me much happier to go to

school.”

根据短文内容,判断下列句子的正误,正确的用“A,错误的用“B。

( )1. The teenagers in the UK usually don't have enough time to sleep.

(     )2. One school in the UK has realized that it's good for kids to get more

sleep.

(     )3. The students can pay more attention to their studies if they get enough sleep.

(     )4. The teenagers can get ready for the day earlier than the adults.

(     )5.Many teenagers feel happy about the later start because they don't need to go to school in a hurry.

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