【简答题】移动机器人如图所示,由两个标准驱动轮和一个小脚轮组成。请问该移动机器人的自由度是多少?机动性是多少?
【判断题】普朗克的能量子假设是为解释光电效应的实验规律提出来的
【单选题】当跳开一台300MW发电机组时,电力系统频率【 】
【单选题】— ______unhappy boy he is ! ____?— He has failed the final examination.
B.
How; What is happening
C.
How an; What was happened.
D.
What an; What has happened
【单选题】—A talk on American culture in the school hall yesterday afternoon. —It’s a pity. I missed it.