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问题 单项选择题

有一对称三相负载，每相的R=16Ω，XL=12Ω，△接法，接在线电压为380V的电源上使用时，电路的功率因数是（）

A.1.33

B.0.75

C.0.6

D.0.8

答案

参考答案：D

单项选择题 A1型题

冠心病的确诊手段是（）

A.胸部X线

B.常规心电图

C.超声心动图

D.动态心电图

E.冠状动脉造影
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单项选择题

Originally introduced by Netscape Communications, (1) are a general mechanism which HTFP Server side applications, such as CGI (2) , can use to both store and retrieve information on the HTTP (3) side of the connection. Basically, Cookies can be used to compensate for the (4) nature of HTTP. The addition of a simple, persistent, client-side state significantly extends the capabilities of WWW-based (5) .

A．Browsers

B．Cookies

C．Connections

D．Scripts
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