— Yes, they can.

读短文，掌握其大意，然后从A、B、C、D四个选项中选出一个可以填入相应空白处的最佳答案。

    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 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.   5workers 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 professionals (专业人士) plant and  10  the trees.

①人从越高的地方跌落下来，受伤就越严重，这说明人在下落的过程中所受重力越来越大；

②放在桌面上的书本，其受到重力的方向与桌面是否水平无关，总是竖直向下的；

③游泳时，人的手用力向后划水，人就向前运动，则使人向前运动的力是手施加的；

④放在地面上的纸箱，用力推它时它就运动，不推它时它不动，这说明力的作用效果之一是维持物体的运动．

上述说法中，其中错误的有____；正确的有____．（选填序号，多选或少选均不得分）