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如图所示是小华物理学习小组探究“滑动摩擦力大小与什么因素有关”的实验.

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同类题3

阅读下列短文,从每题所给的四个选项(A、B、C和D)中选出最佳选项。

A

    When I was a little kid, a father was like the light in the fridge. Every house had one, but no one really knew what either of them did when the door was shut.

    My dad left the house every morning and always seemed glad to see every one again at night. He opened the jar of pickles when no one else at home could. He was the only one in the house who wasn't afraid to go into the basement by himself. 

    Whenever it rained, he got into the car and brought it around to the door. When anyone was sick, he went out to get the prescription(处方) filled. He set mousetraps. He cut back the roses so the thorns(刺) wouldn't hurt you when you came to the front door. He oiled my roller skates, and they went faster. When I got my bike, he ran alongside me for at least a thousand miles until I got the hang of it. He signed all my report and cards. He took a lot of pictures, but was never in them. He tightened up Mother's sagging(松垂的) clothesline every week or so.

    I was afraid of everyone else's father, but not my own. 

    Whenever I played house(玩过家家), the mother doll had a lot to do. I never knew what to do with the daddy doll, so I had him say, “I'm going off to work now,” and threw him under the bed.

    When I was nine years old, my father didn't get up one morning and go to work, he went to the hospital and died the next day. 

    There were a lot of people in the house who brought all kinds of good food and cakes. We had never had so much company before.   

    He never did anything; I didn't know his leaving would hurt so much.

同类题5

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    A Chinese consortium(联盟)led by China Railway Corp will participate in bidding for a high-speed railroad linking Singapore and Malaysia in 2018, marking another step in China's ambitious strategy to export its high-speed railway technologies to Southeast Asia.

    The consortium, consisting of eight companies including CRRC, China Railway Construction Corporation Ltd, China Railway Signal and Communication Co and Export-Import Bank of China, covers the design, construction, telecommunication, financing, operating and maintenance(维护)sectors for the high-speed rail network.

    A joint tender(招标)for the Kuala Lumpur-Singapore high-speed rail project was issued by the Malaysian and Singaporean government-owned utilities(公用事业)—MyHSR Corp and SG HSR,on Dec 20.According to a joint statement released by the two companies, the potential bidder would be responsible for the design, construction, financing, operating and maintenance of rolling stock and railway systems for the double-track line with a designed speed of 350 kilometers per hour.

    The tender is open to all companies, regardless of their location. A tender briefing will be held in Kuala Lumpur on Jan 23, and proposals need to be submitted by June 29. Submissions will be evaluated based on technical merit(优点), commercial robustness, financial sustainability and price. The preferred bidder will be selected by the end of next year. The governments of both countries signed a bilateral(双边的)agreement late in 2016 to begin the project. According to the agreement, the high-speed rail link is expected to become operational by Dec 31, 2026, and will cut travel time between Kuala Lumpur and Singapore to just 90 minutes.

    “The move indicates that China's State-owned enterprises have stopped cruel competition to hurt each other,” said Du Chunbu, a professor of rail transportation at Beijing Jiaotong University. “Instead, they have started to form a consortium to better compete with companies from Japan, South Korea, Germany and Canada by bringing their specialties into play.”