in order to, so as to, to do, in order that, so that都可以表示“为了，以便于”，辨析如下：
（一）in order to do，按照正常逻辑使用即可，无特别限制，如：
- Putin, the theory goes, is willing to stoke a civil war in order to keep Ukraine from turning to the West. 根据这种理论，普京愿意发动一场内战，以便于组织乌克兰转向西方。 (CNN)
- In order to understand how the human body works, you need to have some knowledge of chemistry. 为了弄清楚人的身体是怎样运作的，你需要具有一些化学知识。(CNN)
（二）so as to do，不用在句首，如：
- Veata and her parents spoke in Khmer, very softly and quickly, so as to prevent me from understanding. 为了防止我听明白，Veata和她的父母说高棉语，又轻又快。 (NEWYORKER)
- She also proposed the development of a Welsh stock exchange so as to provide Welsh businesses with access to capital. 她还建议成立威尔士股票交易所，以便于为威尔士的商业公司提供接触到资本的途径。(BBC)
