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    Have you e  ____  planted a few trees on Tree Planting Day?
    Each year, many of people, both old a ____  young, plant a lot of trees. But this may not be the best w____ to make your home a greener place. Last week, we v ____ a park in Hebei. We were s ____ to find most of the trees had been burnt. The workers told us that the trees d ____ soon after they were planted because they were not watered well enough. So the workers burnt them and changed the trees for new trees to be planted this year. On a card found in one of the trees, a student w ____  . “I hope this tree will g ____ up with me to become the backbone(栋梁) of our country.” The workers said that the survival of the trees was really more important t ____  how many trees were planted.
    Some people in Beijing now have a new idea that they can donate some m ____   and let professionals plant and take care of trees.

乙炔是一种重要的有机化工原料，以乙炔为原料在不同的反应条件下可以转化成以下化合物．完成下列各题：