制作徒手切片的正确顺序是（　　）

①把切下的薄片放入水中　②把新鲜的叶片平放在木板上

③用毛笔蘸取最薄的一片，制成临时切片　④用两片叠加刀片迅速切割．

填空

9 ＋  ____  ＝ 12       ____ ＋ 5＝18        4＋ ____ ＝12

7＋   ____ ＝15       5＋   ____  ＝12     8＋  ____   ＝16    

根据短文理解, 从A、B、C三个选项中选择最佳答案填空。

    Have you ever planted a few trees on Tree Planting Day? Each year, millions of people, both 1, plant a lot of trees. But this may not be the best way to make your home 2.

    Last week we visited a park in Hebei. We were  3 to find most of the trees had been burned. The workers told us that the trees  4 soon after they were planted because they weren't watered well enough. 5 workers burned them and cleaned the place for 6 trees to be planted this year. 7 a card found in one of the dead trees, a student wrote, "I hope this tree will grow up with me to  8 the backbone(栋梁) of our country." The workers said that the survival(存活) of the trees was really more important than 9 trees were planted.

    Some people in Beijing now have a new idea that they can donate(捐赠) some money and let professional (专业人士) plant and 10  the trees.