可燃气体检测仪宜安装于无冲击、无振动、无强电磁干扰的场所,且周围留有不小于5m的净空 发布时间:2017-05-06 12:10 │ 来源:www.tikuol.com 题型:判断题 问题: 可燃气体检测仪宜安装于无冲击、无振动、无强电磁干扰的场所,且周围留有不小于5m的净空。()
题型:判断题 ---Must we leave the classroom now?---No, you _____. You _____ leave after the bell rings.A.mustn't; are allowed toB.don't have to; mightC.needn't; can D.can't; are supposed to 查看答案