17 . You have to keep dangerous chemicals meeting in the safe place 18. Police had to break the meeting up 19 They may use that room for the classroom 20 you must wash your hands
1 câu trả lời
`17.` Dangerous chemicals meeting have to be kept in the safe place (by you).
`-` keep - kept - kept: giữ
`18.` The meeting had to be broken up by police.
`-` break - broke - broken
`19.` That room may be used for the classroom (by them)
`20.` Your hands must be washed (by you).
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`-` Bị độngcủa động từ khuyết thiếu:
$(+)$ S + modal verb + be + V(pp) + (by O)