Activity, Motion, Motive, Motiva

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.