two- step freezing的用法和样例：
例句
- As far as cryostorage of recalcitrant seeds is concerned, vitrification and two-step freezing have been applied in many studies.
顽拗性种子的低温保存，应用较多的是玻璃化法和两步法。 - Alkyl polyglucosides were prepared from glucose and lauryl alcohol by one step reaction using p-toluenesulfonic acid and dodecyl benzene sulfonic acid as catalysts respectively.
分别采用对甲苯磺酸和十二烷基苯磺酸为催化剂进行了一步法由葡萄糖和月桂醇制备烷基糖苷的工艺研究。
