A、Every day of the week. B、Once every two weeks. C、Once a week. D、Twice a week. D

Hi. My name is John Hilton. I’m your teaching assistant for Chemistry, Professor Smith’s class. Let me explain a little about this lab section. It’s a required meeting, twice a week. I expect you to do all the experiments and keep the results  in your lab notebook. I’ II collect the notebooks every two weeks. You’ 11 be graded on your lab notebooks, your attendance,  and quizzes. But the most important information I want to give you today is about the safety procedures.
    First of all, you must wear shoes that cover your feet in the lab. That means you can’ t wear thongs or sandals. Tennis  shoes are OK. Aim, don’t wear clothes that have loose, baggy parts, like long scarves and necklaces or loose belts. They could get caught in something or fall into a liquid.
    Another important safety precaution is cleaning up. Be sure to put the waste in the correct containers. We call’ t mix liquid with paper. This is extremely important. I don’t want any fires in this room.
    You are responsible for washing out your own lab equipment and putting it away. If you don’ t do this, I will deduct points from your grades. I’m not going to clean up after you.
    OK. That’s about all for this meeting. Our first regular class will be next week. Be sure to get a lab notebook before then. Also, let Professor Smith know that you are attending this section.