2016年四平事业单位:They are off to a great start. What does "off" mean here?

They are off to a great start. What does "off" mean here? They are off to a great start中的"are off to"是固定搭配吗? they're off to a great start. They are trying to come up with a solution to problem.为什么solution 用to ? A few readers said they are going to learn a new language. I don't know when they are going to have a welcome party. I don't know when they are going to have a welcome party. They are teachers and don’t realize __________ to start and run a company. they are subflush to ......怎么翻译 They are listening to their teacher 帮帮忙