【单选题】流体在流动过程中,流速 的关系是( )。
【单选题】A good way to train an animal to do something quickly is to_____. A make the action easy
【单选题】If you have difficulty_______a decision,wearing red_______it easier for you to take action.
【单选题】流体在流动的过程中,流速u和管道直径d的关系是( )
【单选题】Obviously the only way to make people realize that an action is morally wrong is to punish them if they ________ it.