皮皮学，免费搜题
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搜题
【单选题】
通信系统的作用是将信息从信源传送到一个或多个目的地。我们把能够实现信息传输的一切设备和传输媒质(信道)的集合称为A.
交换系统
B.
传输系统
C.
发送系统
D.
通信系统
拍照语音搜题，微信中搜索"皮皮学"使用
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知识点：
皮皮学刷刷变学霸
举一反三
【单选题】1) The writer uses the example of two drivers to teach the students that ______.
A.
the gap between the rich and the poor is huge
B.
rich people often don’t drive luxurious cars
C.
with wealth, appearances can be deceiving
D.
the rich are invisible
【判断题】The writer was not happy about his having to teach algebra and geometry, but he did not mind having to walk a mile along the dusty road to the Park.
A.
正确
B.
错误
【单选题】The writer uses the example of two drivers to teach the students that ______.
A.
the gap between the rich and the poor is huge
B.
rich people often don’t drive luxurious cars
C.
with wealth, appearances can be deceiving
D.
the rich are invisible
【单选题】下面说法中关于E-R图说法有误的是
A.
E-R图也称实体-联系图(Entity Relationship Diagram)。
B.
构成E-R图的3个基本要素是实体对象、属性和联系
C.
E-R图中用矩形表示实体型；用椭圆表示实体的属性。
D.
可以使用E-R图来设计数据表。
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