• Activity
  1. 活跃、繁忙( Uncountable) the situation in which a lot of things are happening or people are moving around
  2. 行动、活动 the work of a group or organization to achieve an aim
  3. 娱乐活动 something that is done for enjoyment, especially an organized event

There was a lot of activity in preparation for the Queen’s visit.

He was found guilty of terrorist activity. / criminal activities

His spare-time activities include cooking, tennis, and windsurfing.

• Motion

  动、运动、移动 the act or process of moving, or a particular action or movement

They showed the goal again in slow motion.

• Motive 动机 a reason for doing something

Why would she have killed him? She has no motive.

• Motivation
  1. 积极性、干劲儿 enthusiasm for doing something
  2. 动机、诱因 the need or reason for doing something

He’s a bright enough student - he just lacks motivation.

What was the motivation for the attack?

• Motivate
  1. 使产生动机、激起 to cause someone to behave in a particular way
  2. 激励 to make someone want to do something well

Like so many people, he’s motivated by greed.

Teaching is all about motivating people to learn.