1、be used to doing习惯做某事

Be used to doing he is an experienced driver and he is used to driving in all kinds of weather. 

他是一位有经验的驾驶员，他习惯于在各种各样的天气情况下开车。

2、used to do过去经常做某事

Things like transport, purchasing and warehousing used to be considered merely part of the cost of doing business, and were often managed as separate entities. 

象诸如运输、原料采购、仓库存储之类的事情，过去常被认为仅仅是业务成本的一部分，而且被当作单独的组织进行管理。

3、be used to do被用来做……

In addition to producing electricity, gas is used to make fertiliser and generate heat for buildings and industry.

除了发电，天然气还可以用来制造肥料、为建筑物和工业生产供暖。

参考双语例句：

No one ever claimed the transition from a hundred-year-old British colony to a Special Administrative Region of China is easy, but we Hong Kong people are used to doing the impossible.

虽然从来没有人说过，由百年英国殖民地过渡至中国的特别行政区是一件容易的事，但是，香港人已惯于创造奇迹。

To deal with this question, what officials used to do was never to set a turnout target in advance and always to say afterwards that the turnout rate was very "satisfactory".

对于投票率这个敏感问题，以往官员的做法是，投票前拒绝订出投票率的目标，而事后必定说投票率是非常“满意”的。

The first designed to be used to do under the searchlight beams in the ceiling effect, but the blending of domestic searchlight uneven, hanging upside down under the stability of the poor have to abandon the use of searchlights lighting design plan. acehk.com

最早设计使用探照灯在顶棚下做光束效果，但国产探照灯的混色不均匀、倒挂下稳定性不佳都让灯光设计放弃使用探照灯的计划。