题干

做匀速直线运动的甲乙两个物体,他们的速度之比是3:1,通过的路程之比是2:5,则所用的时间之比为(    )

A:3:1

B:2:15

C:6:5

D:3:2

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答案(点此获取答案解析)

B

同类题1

阅读下面材料, 在空白处填入适当的内容(一个单词)或括号内单词的正确形式。

    On the ____ (one) day of the new term, I met my new headmaster at the school gate. "Follow me, please!" he said. He had ____ quiet, kind voice. He took me into my new classroom and ____ (leave). In front of me, thirty pairs of eyes looked at me. I knew he had told the students that I was blind. I could almost feel the question behind their eyes: "Blind?" I felt the answer too: "If she's blind, this should be good!" I heard quiet ____ (voice) in a corner of the classroom. For a moment, I felt afraid. I knew at once that I had to be ____ (strong) than before.

    "Class," I said as ____ (loud) as I could. "I may be blind. But I am not foolish. Take those naughty smiles off your faces, and stop talking, please!" Of course, I could not see their faces; I just guessed that some of them were smiling. The class were quiet. They were very surprised. I knew that I had done the right thing.

    ____ the days went by, the students had more surprises. I could smell when the children were eating sweets. I could easily hear combs going through hair, students ____ (pass) messages, and so on. Once I found a girl passing a message to a friend. I took the message to the teachers' room. A teacher read it to me. On one side it said, "Do you think she can see?" On the other it said, "I think so. She always knows ____ we're doing."

    Soon the students stopped being naughty, and started to work hard. Before long, they brought in photos of ____ (they) families for me to look at. I knew then they were my friends. I also knew they had forgotten that I could not see.