题目

       Jack  is   1  American boy. He is one of the best students in his class,he is   2     his lessons,and he can speak  3   Chinese. But Jack enjoys  4    best.        One day,he  5   his homework, instead（而是/相反） he went to a swimming pool. When he was swimming, suddenly（突然）he heard a scream(尖叫). “Excuse me ,what can I do   6   you,sir?”, he asked , “Yes ,I would like someone   7    me how to swim?” The man answered. “Really?You can’t swim?Ok, let me   8   you.,I’m sure you can swim very well soon.以下是制作和观察洋葱表皮细胞临时装片的图示。请分析回答：（1）图一中，制作临时装片的正确操作顺序是： （填序号） 。在图二中观察细胞时发现有气泡，可能是图一的哪个步骤操作不规范引起的? （填序号）。（2）要将图二的甲转化成乙，应转动 ，换用 （低倍或高倍）物镜观察。若要使视野中的物像更清晰，应调节显微镜的 。若视野中光线太强，物像边界不明，此时应调节 改用较小光圈，以减弱视野中的光线。