国航机队:they're off to a great start.

they're off to a great start. 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? To wish me a happy birthday,they're going to pull on my ear 21 times,once for each year. They don't always say what they're going to do We're off to never never land是啥意思?? 翻译:they don't want me to play with them.they said "you're ugly" A;Five oranges,please.B;How _________ are ________ ? A;They're six dollars. They go to ( ) a doctor They're both convinced that a sudden passion joined them.