i(am used to)(used to)swimming in cold water.

问题描述:

i(am used to)(used to)swimming in cold water.

应该用“am used to”
be used to doing sth 意思为“习惯做...",此处的 ”to“为介词,后面跟动名词;
used to do sth意思为“过去常常做...”,此处的“to”为不定代词,后面跟动词原形.