九年义务教育初中生物上册教材中共有演示实验引个，分组实验16个；由于受季节和气候的限制，有的实验无法取得现成的原材料而不能进行。如上册（实验二）所用的洋葱或蒜瓣，这个实验一般在九月中旬进行，此时市场上无洋葱购买，又如上册《实验八》按一般进度，此时将近10月上 In the nine-year compulsory education junior middle school biology textbooks, there were a total of demonstration experiments and 16 grouped experiments. Due to the limitations of the season and the climate, some experiments could not obtain the ready-made raw materials and could not be carried out. In the onion or garlic clove used in the previous book (Experiment 2), this experiment was generally conducted in mid-September. At this time, there was no onion purchase on the market, and the above book “Experiment 8” was on a normal schedule. At this time, it was nearly 10 months.