【单选题】Remember:don't touch anything in the laboratory unless the teacher tells you________. [ ]
【单选题】Don’t touch him, for he is a ______person.
【单选题】-- Don't touch it. It's dangerous. --______
【单选题】I'd ______ you didn't touch that, if you don't mind.
【单选题】I' d ______ you didn't touch that, if you don't mind.
【单选题】This sign means ______. [ ]