某变速箱中有甲、乙、丙三个齿轮，如图所示，其半径分别为r1、r2_爱下问搜题

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问题选择题

某变速箱中有甲、乙、丙三个齿轮，如图所示，其半径分别为r₁、r₂、r₃，若甲轮的角速度为ω，则丙轮边缘上某点的向心加速度为（　　）

A.

B.

C.

D.

答案

答案：A

完形填空

When I settled in Chicago，my new city seemed so big and unfriendly. Then I had a         problem and had to go to hospital for a        check-up.
It seemed a small        compared to the one I was about to face, but things started to go    right from the beginning. Not having a car or        the city, I was depending on a couple of buses to get me from A to B.        I’d left myself plenty of time, soon it was        I was going to be late, as I had mistakenly got on a bus that was taking me in the       direction.
I      the bus and stood on the pavement(人行道) not knowing what to do, I looked into the eyes of a        , who was trying to get past me.      , instead of moving on, she stopped to ask if I was        . After I explained my        to her, she pointed to a bus stop across the street, where a bus would take me back into the city to my        . Sitting there waiting, I felt        that someone had been willing to help.       , hearing a horn （喇叭）nearby, I looked up to see a car with my new friend       at me to get in. She had returned to offer me a       to the hospital.
Such unexpected         from a stranger was a lovely gift to receive. As I climbed out of the car at the hospital and turned to thank her, she smiled and told me not to lose       , for all things are possible.

A．appreciating

A．Surprisingly

D．appointment

A．disappointed

B．Without doubt

A．waving(招手)

C．staring(盯着)

判断题

泵站自动控制装置的投资占整个工程基建投资的比例较大，而投入运行后，若符合技术要求，不仅可以减少管理人员，同时还可以节约电耗。