单项选择题
The closed-loop system differs from the open-loop system by（）
A.the lack of a feedback B.the presence of a feed back C.the lack of a computer D.the presence of a computer
单项选择题 From the passage, we can learn that the simplest controller action is（）
单项选择题 Which kind of the following controllers is the most sophisticated controller?（）
单项选择题 The word “offset” most probably means（）
