【判断题】在s左半平面的适当位置附加开环实数零点,一般可以改善系统稳定性。
【单选题】单项选择(每题1分) We’ve been looking at houses but haven’t found _____ we like yet.
【单选题】We’ve been looking at cars but haven’t found____we like yet.
【单选题】(2013·高考辽宁卷)—What do you think of the house? —________It’s everything we’ve been looking for.