progressive freezing的用法和样例：
例句
- After embryo transfer, the pregnancy and lambing rates within vitrification group were higher than that of slow freezing group.
将冷冻解冻后的绵羊囊胚移植后，玻璃化冷冻组的怀孕率和产羔率明显高于慢速冷冻法的。 - Extracting can also be done by partially freezing the salt solution.When this is done, the water freezes first, leaving the salts in the remaining unfrozen solution.
局部冷冻法是使盐水部分冷冻，这时先行冷冻的是水，盐则留在未曾冻结的液体中。
