Please choose the correct ending to complete the given sentence: Education and Communications: [header] How to behave in a school science lab [title] Know about all safety procedures. [step] If an emergency does occur, it is important that you know the correct way to act. All safety and emergency procedures should be discussed at the beginning of the school year.

Ending1: If there is any question as to whether you are at risk, you can ask your school superior. [substeps] Stay alert to potential dangers so you are prepared in case anything is fatal for your safety. Ending2: In addition, relevant safety measures should be reviewed before each experiment. [substeps] If you are unsure about a specific process, ask your teacher so that you will know exactly what to do. Ending3: You should take a look at all the equipment and make sure everything is in good working order. [substeps] Keep your classroom doors locked and other doors locked, both in and out, even during a scientific lab. Ending4: If you are running, jumping, and doing dangerous experiments, make sure you know what to do. If there is a drop in the temperature, for example, evacuate your area.

Answer format: ending1/ending2/ending3/ending4