1）DECIDE ON 决定,选定 + 名词, 通常理解为“对什么作出决定” 而 on 是介词。
Examples:
1. Don't decide on important matters too quickly.
不要过于匆忙地对重要的事情作决定。
2. Decide on a career
选定一种职。
3. We'll decide on our team as and when we qualify for the competition.
我们来决定自己的队到什么时候才有资格参加比赛.
4. If you are not planning on breastfeed, you have to decide on a formula.
如果你不打算喂母奶，那麽你得决定选一种婴儿奶粉（水）。
2) DECIDE v. 决定,判决
Examples:
1. Don't decide on important matters too quickly.
不要过于匆忙地对重要的事情作决定。
2. He decided to get married.
他决定结婚。
3. A chance meeting decided my career.
偶然的会面决定了我的事业。
4. That decided me to leave my job.
那件事使我决定离职。
5. It's difficult to decide between the two.
对这两者，不易做出抉择。
你可以比较一下各自的例子，然后得出自己的想法吧。
1）DECIDE ON 决定,选定 + 名词, 通常理解为“对什么作出决定” 而 on 是介词。
Examples:
1. Don't decide on important matters too quickly.
不要过于匆忙地对重要的事情作决定。
2. Decide on a career
选定一种职。
3. We'll decide on our team as and when we qualify for the competition.
我们来决定自己的队到什么时候才有资格参加比赛.
4. If you are not planning on breastfeed, you have to decide on a formula.
如果你不打算喂母奶，那麽你得决定选一种婴儿奶粉（水）。
2) DECIDE v. 决定,判决
Examples:
1. Don't decide on important matters too quickly.
不要过于匆忙地对重要的事情作决定。
2. He decided to get married.
他决定结婚。
3. A chance meeting decided my career.
偶然的会面决定了我的事业。
4. That decided me to leave my job.
那件事使我决定离职。
5. It's difficult to decide between the two.
对这两者，不易做出抉择。
decide on 意思是‘就.....作出决定, 决定要....’
decide 动词‘决定’
decide: to make a choice about what you are going to do 决定
decide on: to choose someone or something from a number of possible choices 选定
标签：decide,区别
