根据句意及首字母的提示,填写所缺的单词

根据句意及首字母的提示,填写所缺的单词1.do you know how to o____ on the machine?2.i can see an i____ in the middle of the lake3.have you b____ the baby's milk yet?4.salt is p_____ in east and south china5.a machine is made of m______