Please look _______ the pictures on the wall.

从12个同类产品（其中10个是正品，2个是次品）中任意抽取3个，

（1）3个都是正品；

（2）至少有1个是次品；

（3）3个都是次品；

（4）至少有1个是正品，

上述四个事件中为必然事件的是____  （写出所有满足要求的事件的编号）

    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 a 2 place.
    Last week we visited a park in Hebei. We were3 to find most of the trees had been burned. The workers told us that the trees 4soon 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.