问题
选择题
Don’t touch anything in the lab unless____.
A. to be allowed B. allowed C, to be allowing D.allowed to
答案
答案：D
考查从句省略。完整的句子是：unless you are allowed to touch
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Don’t touch anything in the lab unless____.
A. to be allowed B. allowed C, to be allowing D.allowed to
答案：D
考查从句省略。完整的句子是：unless you are allowed to touch