3.Do not eat，drink，or chew gum in the lab.Do not use lab glassware as containers for food or drink. 4.Know the positions and operating procedures(程序) of all safety equipment，including the first-aid kit and the fire extinguisher(灭火器).Know where the fire alarms and the exits are. 5.Check the labels(标签) on chemical bottles twice before removing any of the chemicals.Take only as many chemicals as you need. 6.Most chemicals in the lab are considered to be dangerous.Do not touch，taste，or smell any chemicals unless specifically asked to do so.