Most people know something about the greenhouse effect. Factories send gasses such as carbon dioxide, or CO₂, into the atmosphere, the air around the earth. In the past, this wasn't a problem because trees absorbed the CO₂. But now people in many countries are cutting down billions of trees all around the world. At the same time, factories are sending more CO₂ into the atmosphere. It's difficult to believe, but factories put billions of tons of CO₂ into the atmosphere every year. One ton is over 2000 pounds, so it is a lot of pollution. There is too much CO₂ and there aren't enough trees, so the world is getting warmer. In other words, we have a greenhouse effect. This is terrible for the environment.

    What can we do about this? Firsts we can stop using so much coal and oil. We can learn to use different kinds of energy: the sun, wind, steam from volcanoes，and heat from inside the earth. Second, instead of cutting down trees, we should plant more trees. One tree can absorb ten pounds of carbon dioxide every year.

    The trees are good for the earth's atmosphere and for Guatemala (拉丁美洲国家危地马拉).In small towns and villages in Guatemala, most women are poor and have hard lives. Trees help them in three ways. First, the Connecticut factories pay them to plant the trees. Their pay is com, not money. The com is good for their children. Second, these women know a lot about their environment. They know where to plant when to plant, and what kinds of trees to plant. For example，they plant many fruit trees. The fruit gives them vitamins for their families^, diets. Other trees are good for firewood. In a few years, the women won't spend so much time looking for firewood. Third, all these trees are good for the soil. Now rain can't wash the soil down from the mountains so easily.

    This plan isn't enough to stop the greenhouse effect. However, it's a start. The woman of Guatemala are helping themselves and helping their environment.

一日的春光

冰心

       ①去年冬末，我给一位远方的朋友写信，曾说我要尽量的吞咽今年北平的春天。

       ②今年北平的春天来的特别的晚，而且在还不知春在哪里的时候，抬头忽见黄尘中绿叶成阴，柳絮乱飞，才晓得在厚厚的尘沙黄幕之后，春还未曾露面，已悄悄的远引了。

       ③天下事都是如此——

       ④去年冬天是特别地冷，也显得特别地长。每天夜里，灯下孤坐，听着扑窗怒号的朔风，小楼震动，觉得身上心里都没有一丝暖气。一冬来，一切的快乐、活泼、力量和生命，似乎都冻得蜷伏在每一个细胞的深处。我无聊地安慰自己说：“等着罢，冬天来了，春天还能很远么？”

       ⑤然而这狂风、大雪，冬天的行列，排得意外地长，似乎没有完尽的时候。有一天看见湖上冰软了，我的心顿然欢喜，说：“春天来了！”当天夜里，北风又卷起漫天匝地的黄沙，忿怒的扑着我的窗户，把我心中的春意又吹得四散。有一天看见柳梢嫩黄了，那天的下午，又不住地下着不成雪的冷雨，黄昏时节，严冬的衣服，又披上了身。

       ⑥九十天看看过尽——我不信了春天！

       ⑦几位朋友说：“到大觉寺看杏花去罢。”虽然我的心中始终未曾得到春的消息，却也跟着大家去了。到了管家岭，扑面的风尘里，几百棵杏树枝头，一望已尽是残花败蕊；转到了大工，向阳的山谷之中，还有几株盛开的红杏，然而盛开中气力已尽，不是那满树浓红、花蕊相间的情态了。

       ⑧我想，“春去了就去了罢！”归途中心里倒也坦然，这坦然中是三分悼惜，七分憎嫌，总之，我不信了春天。

       ⑨四月三十日的下午，有位朋友约我到挂甲屯吴家花园看海棠，“且喜天气晴明”——现在回想起来，那天是九十春光中惟一的春天——海棠花又是我所深爱的，就欣然地答应了。

       ⑩东坡恨海棠无香，我却以为若是香得不妙，宁可无香。我的院里栽了几棵丁香和珍珠梅，夏天还有玉簪，秋天还有菊花，栽后都很后悔。因为这些花香，都使我头痛，不能折来养在屋里。所以有香的花中，我只爱兰花、桂花、香豆花和玫瑰，无香的花中，海棠要算我最喜欢的了。

       ⑾海棠是浅浅的红，红得“乐而不淫”，淡淡的白，白得“哀而不伤”，又有满树的绿叶掩映着，秾纤适中，像一个天真、健美、欢悦的少女，同是造物者最得意的作品。

       ⑿斜阳里，我正对着那几树繁花坐下。

       ⒀春在眼前了！

       ⒁这四棵海棠在怀馨堂前，北边的那两棵较大，高出堂檐约五六尺。花后是响晴蔚蓝的天，淡淡的半圆的月，遥俯树梢。这四棵树上，有千千万万玲珑娇艳的花朵，乱烘烘的在繁枝上挤着开……

       ⒂看见过幼稚园放学没有？从小小的门里，挤着的跳出涌出使人眼花缭乱的一大群的快乐、活泼、力量、生命；这一大群跳着涌着的分散在极大的周围，在生的季候里做成了永远的春天！

       ⒃那在海棠枝上卖力的春，使我当时有同样的感觉。

       ⒄一春来对于春的憎嫌，这时都消失了。喜悦地仰首，眼前是烂漫的春，骄奢的春，光艳的春——似乎春在九十日来无数的徘徊瞻顾，百就千拦，只为的是今日在此树枝头，快意恣情的一放！

       ⒅看得恰到好处，便辞谢了主人回来。这春天吞咽得口有余香！过了三四天，又有友人来约同去，我却回绝了。今年到处寻春，总是太晚，我知道那时若去，已是“落红万点愁如海”，春来萧索如斯，大不必去惹那如海的愁绪。

       ⒆虽然九十天中，只有一日的春光，而对于春天，似乎已得了酬报，不再怨恨憎嫌了。只是满意之余，还觉得有些遗憾，如同小孩子打架后相寻，大家忍不住回嗔作喜，却又不肯即时言归于好，只背着脸，低着头，撅着嘴说：“早知道你又来哄我找我，当初又何必把我冰在那里呢？”

I can’t decide ______.

You mean the purple blouse or the blue one?

位于我国西部的直辖市是（    ）