Laboratory work is your chance to learn science firsthand. It can be fun but you must be careful to prevent injury. Listen closely when your teacher reads and explains the rules before your first lab lesson.

LABORATORY  RULES
Throughout the lesson	·Do not enter the science lab without the teacher’s permission. No food or drinks are to be allowed in the science lab.
Before the Experiment	·Read all instructions carefully before every experiment. · Prepare all apparatus（仪器）and arrange them so that you will not knock them over while doing the experiment.
During the Experiment	·If you are unsure of how to use any apparatus or how to operate, ask your teacher for help. ·Never smell or taste chemicals unless your teacher gives permission.
After the Experiment	·Wash all apparatus after use and return them to the places where they were. ·Throw waste materials in proper waste baskets.
First Aid	·Report all accidents to your teacher immediately. ·If you spill（溅出）any chemicals onto your body or clothing, wash with plenty of water and report to your teacher.

   Your teacher will probably tell you the rules above ___________ the first lab lesson.

A．before

B．since

C．during

D．after

Before every experiment, you should ___________.

A．taste the chemicals first

B．clean all the apparatus

C．read all instructions carefully

D．report all the accidents to the teacher

When you are not sure how to use all apparatus, ___________.

A．try them on your own	B．read the rules carefully
C．ask your teacher for help	D．put them back

  It is clear that you can ___________.

A．bring food into the lab	B．enter the lab at any time
C．smell chemicals as you like	D．learn science directly in the lab

If you get chemicals on the clothing, you can find ways to solve it in the part ___________.

A．Before the Experiment	B．First Aid
C．During the Experiment	D．After the Experiment