His parents thought he was working very hard in the room, _____in fact, he was chatting with his fri

题干

His parents thought he was working very hard in the room, _____in fact, he was chatting with his friends on the Internet.

A：whe

B：where

C：which

D：while

上一题下一题 0.0难度选择题更新时间:2016-03-16 04:09:15

D

①实验室备有的定值电阻R₀有以下几种规格：

A.10Ω，2.5 W； B.50Ω，1.0 W； C.150Ω 1.0 W； D．I500Ω，5.0 W

本实验R₀应选用____，其作用是____；

②根据乙图所作出的图象求得该电池的电动势E为____V，内电阻r为____Ω．（保留两位有效数字）