I am a junior school student , and I'm in Grade Three. I'm busy with my studying every day . Look at my course schedule.

已知圆环的外圆半径为46mm，内圆半径为27mm，求圆环的面积（利用计算器计算，结果精确到十位）．

联合国是当今世界最重要的国际组织之一，关于这一组织的叙述不正确的是（   ）

①1942年《联合国家宣言》签订标志这一组织正式形成

②雅尔塔会议决定战后建立联合国

③1947年联合国通过决议在中东地区实行印、巴分治

④联合国的成立是世界经济全球化的一个重要表现

    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.