Don't touch the instruments in the laboratory ________ the teacher allows you to do that. A．unless B...
2022-11-21 16:46:45 194次 2016届江苏省南京市玄武区九年级5月测试（二模）英语试卷（解析版） 单项填空 反馈错误 加入收藏 正确率 : 100%
题目内容：
Don't touch the instruments in the laboratory ________ the teacher allows you to do that.
A．unless B．when
C．though D．because
本题链接：
