非线性电路中常用的非线性器件有 A.
变容二级管等
B.
各类场效应管
C.
双极型晶体三极管 D.
半导体二级管

不定项选择理想电流源与理想电压源之间不能进行等效互换。

单项选择题Have you rented a public bike today? Hangzhou Bus Group, is the organization that operates the Hangzhou public bicycle transportation system. 85 citizens have used the public bicycles over 600times in the past year. They won't have to pay the 200-yuan deposit to use the bikes. The public bicycle system has been running since May 2008. It is cheap and convenient. There are more than 1,600 public bicycle rental stations throughout the city, with more than 40,000 bicycles for citizens and visitors. To use the bikes, people will need to buy a stored value card at 20 Longxiang Qiao. They need to be older than 12 years old and need to show proper ID. The card should have 300 RMB on it. 200 of which is a deposit and the remaining 100 for rental fees. The bike is free for the first hour but costs 1 RMB an hour for the second hour, 2 RMB an hour for the third hour, and 3 RMB an hour after that. The public bicycles are used an average of 100,000 times a day, with ahistorical one-day high of 200,000. If a rented bike travels an average distance of 2 kilometers, 7,500 tons of oil would be saved and co, emission would be reduced by 23,897 tons in a year. (3)How much will Frank pay for renting the public bike in six hours? ( ) A、9 yuan. B、10 yuan. C、18 yuan. D、15 yuan.