what must we do before touching food.“must”有这样问的么?

what must we do before touching food.“must”有这样问的么? We must C----------- your food well before you swallow it what must you do before getting off a train 英语翻译We do what we must because we 翻译We do what we must because we can what "must"i/we/you/he/she/they do and what "must not'' i/we what must he do? what must i do? What must she do 有没有语法错误 We must value what we We must think before we buy. We must tell them what they should do.(词义转换)