(1) think ahead意思是“预先考虑到”。

• Thinking ahead, we might be wise to build the new factory now before prices rise again.
  要预先考虑，在涨价前现在就动手建新厂可能是明智之举。
• We've taken the first step, but haven't yet thought ahead to our next move.
  我们已采取了第一步，但还没想好下一步该怎么走。

 (2) look ahead与think ahead意思相近，指“想到将来，展望未来，为将来做准备或计划”解。

• Everyone should look ahead and save a little money each year for when he retires.
  人人都应未雨绸缪，每年为退休后的生活攒点钱。
• Looking ahead to the future, we can imagine a time when all cars will run on electricity.
  展望未来，我们不难想象一个汽车电动时代的到来。

 (3) see ahead也可作“预先考虑到将来；对未来有了解；为未来做计划”。

• It's difficult to make decisions about one's professional life when things change so fast and one cannot see ahead very far.
  世事变化无常，人也不能对未来预见太远，所以做出择业决定是很困难的。
• Imagine that you can see ahead to the year 2020, what sort of world do you think we shall be living in?
  设想你能够预想到2020年，你认为那时我们将会生活在一个什么样的世界？