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问题 不定项选择

三颗卫星都在赤道平面内绕地球做匀速圆周运动，它们的轨道半径分别为r1、r2、r3，且r1>r2>r3，r2为同步卫星的轨道半径，三颗卫星在运动过程受到的向心力大小相等，则[ ]

A．经过相同的时间，卫星1通过的路程最大

B．三颗卫星中，卫星1的质量最大

C．三颗卫星中，卫星1的加速度最大

D．卫星3的周期小于24小时

答案

BD

单项选择题

The "main storage" normally means that part of internal storage into which instructions and other data must be loaded for subsequent execution or processing. In large computing systems, the term "main storage" is (71) to "memory". "Buffer" mainly indicates a special-purpose storage or storage area allowing, through (72) storage, the data transfer between two functional units having different transfer characteristics. A buffer storage is used between non-synchronized devices or where one is (73) and the other is parallel or between those having different trans far rates. " (74) (memory)" is also a special-purpose buffer storage, smaller and faster than main storage, used to hold a copy of instructions and data obtained from main storage and likely to be needed next by the processor. "Register" is commonly composed of a part of internal storage having a specified storage (75) and usually intended for a specific purpose.

（71）是（）

A.suitable

B.optional

C.choice

D.preferred
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单项选择题

下列情况属于浅Ⅱ度烧伤的是

A．伤及表皮浅层，生发层健在

B．伤及表皮生发层、真皮 * * 层

C．伤及皮肤全层

D．伤及皮下组织
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