"Be good for"、"be good with"、"be good to"、"be good at"是四个表示"好"的短语，但在使用上有所不同。
"Be good for"用来表示某个事物对某个人或事物有益处。例如：
Eating fruits and vegetables is good for your health.
Studying abroad can be good for your career.
"Be good with"通常用来形容某个人的社交能力，表示与某个人相处融洽。例如：
Sarah is good with children, she's a great babysitter.
John is good with people, he can talk to anyone.
"Be good to"用来表示某个人对另一个人友善或体贴。例如：
The teacher is always good to her students, she's very caring.
He was good to me when I was sick, he brought me soup and medicine.
"Be good at"用来表示某个人在某个领域或技能上有很高的水平或专业能力。例如：
Tom is good at math, he always gets top grades.
She's good at playing guitar, she can play any song.
总的来说，"be good for"强调的是事物的益处；"be good with"强调的是人际关系的融洽；"be good to"强调的是人与人之间的友善；"be good at"强调的是技能和能力。