【单选题】"We must take steps to prevent more diseases from becoming serious. We should preserve animal habitats and stop overprescribing antibiotics."
【简答题】如何划分一个复合轮系的定轴轮系部分和各基本周转轮系部分?在下图所示的轮系中,既然构件5作为行星架被划归在周转轮系部分中,在计算周转轮系部分的传动比时,是否应把齿轮5的齿数z 5 计入?
【单选题】We are going to _____ this question at the next meeting. [ ]
【简答题】Eve: We ____________________ take food into the movie theater.Alan: That’s strange. I didn’t see a sign about that.A. can’tB. couldn’tC. don’t have toD. must
【简答题】I was enjoying the busy traffic in South Bombay with people rushing in every possible direction when we got 1 (stick) at a very busy crossroad. As we waited for the signal to turn green, my eyes met u...
【简答题】在图示差动轮系中,已知各轮的齿数z1=30,z2=25, =20、z3=75,齿轮1的转速为200r/min(箭头向上),齿条3的转速为50r/min(箭头向下),求行星架转速nH的大小和方向。
【单选题】下图是行星齿轮机构三元件中的________?