want to:动词不定式,后面加动词,表示想做某事,
如I want to watch TV.我想看电视.
want：及物动词,后面加名词,表示想要某物,
如I want the bigger apple.我想要那个大点的苹果.
need：及物动词,后面加名词,表示想要某物,
如I need money.我需要钱.
need to：动词不定式,后面加动词,表示应该做某事,
如I need to do homework now.我现在要做作业了.
"want to" 结构的用法：
1. I want to visit Paris someday.（我希望有一天能去巴黎。）
2. She wants to learn to play the piano.（她想学弹钢琴。）
3. They want to start their own business.（他们想开办自己的生意。）
4. We want to go on vacation next month.（我们下个月想去度假。）
5. He wants to become a doctor in the future.（他将来想成为一名医生。）
