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问题 选择题

中国北方航空公司某驾客机安全､准时降落在规定跑道上,假设该客机停止运动之前在跑道上一直做匀减速直线运动,客机在跑道上滑行距离为s,从降落到停下所需时间为t,由此可知客机降落时的速度为(    )

        

答案

答案：B

匀减速直线运动的平均速度等于这段时间中间时刻的瞬时速度,因此有B正确.考查匀变速直线运动的规律,由平衡速度求解最简便.

单项选择题

物质生产部门的劳动者所创造的国民收入中，主要用来满足劳动者个人消费及社会消费的部分称为()。

A.保障基金 

B.消费基金 

C.积累基金 

D.管理基金
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单项选择题

Personal computers are used by one person at a time. The largest personal computer, or PCS, can fit on a (1) . Some of these (2) have more than one microprocessor. (3) the primary processor, which is a general-purpose device, a PC may have one or more processors to (4) special kinds of work. Some machines, (5) , have maths processors, others have graphics processors to help process photographs and other illustrations. Still others have (6) processors.
Office workers also use PCS that are not (7) to a network. These machines are used for (8) tasks as word processing, performing financial calculations, and organizing and (9) bodies of information called databases. People use PCS at (10) for some of the same kinds of tasks. They use word processing programs for (11) Communication, financial software for household budgets. Individuals also use their home computers to play (12) and to communicate (13) the internet.
Small, portable PCS are (14) with people who often work away from their desks. The (15) include laptop computers, which can be (16) on the lap; notebook computers, which are about the (17) of a loose leaf notebook; and palmtop, or handheld computers, which can be operated while (18) in the hand. Laptop and notebook computers have the same (19) as desktop computers. Palmtop computers have less power but still (20) some advanced capabilities. For example, they can process household financial data.

二、完形填空

A．in

B．across

C．over

D．above
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