Although it accounts for only 1% of the park，s surface area， Yosemite，s most well known and popular feature is unquestionablyunquestionably adv.无疑地，无可非议地 the valley of the Merced River with its spectacular granite mountains and sheer cliffs. The valley itself was carved by the Merced River over millions of years， gouged and flattened by glaciers. After the retreat of the last of the glaciers a huge lake - Lake Yosemite - formed in the valley. This lake lasted several centuries. As it silted over and disappeared， it left behind the flat floor of the valley which exists now. It has deservedly been described as the most spectacular valley on earth.
One of the most impressive views of the valley - the famous “Tunnel View” or “Discovery View” - is presented to the visitor heading east towards the valley on Highway 140. Passing through the Wawona tunnel， the valley spreads out suddenly before the fortunatefortunate adj.幸运的， 幸福的 traveller. El Capitan can be seen to the left， Half Dome in the center， Cathedral Rocks on the right， and Bridalveil Falls. Cloud，s Rest can be seen in the center of the picture. This vista has been called one of the most photographed on earth. Interestingly， it is about 1000 feet below the point from which the Mariposa Battalion first glimpsed the magnificent valley.
The Indians who lived in the area before the arrival of the white man called the valley “Ahwahnee” - place of the gaping mouth， and identified with this special place， referring to themselves as the Ahwahneechee. They used fire to clear the valley for black oak trees which provided acorns， an important source of food. These trees can be seen in many photographs of the valley floor.
Of the 4 million or so people who might visit Yosemite in a year， about 90% of them go to Yosemite Valley， although the valley itself represents only 1/2 of 1% of the total area of the park. From Yosemite Lodge， which sits near the edge of the valley， the precipitousness of the valley，s walls is particularly obvious.
Yosemite Valley is， in essence， a 7 mile long canyon. It is a valley or gorge carved by the Merced River and cut by the glaciersglacier n.冰河. which flowed through the valley on three occasions. It is about 1 mile wide. The end of Yosemite Valley is generally considered to be Half Dome， where the valley splits into a Y， the north arm being Tenaya Canyon and the south arm the Little Yosemite Valley， through which the Merced River flows over Vernal and Nevada Falls. The end of the valley can be seen in the picture below from Glacier Point.
The glaciers which visited the area repeatedly covered all but the highest landformslandform n.地形 in this area - El Capitan， Bounding Ridge， Cloud，s Rest， and Sentinel Dome.
Yosemite Falls
The collection of waterfalls in Yosemite is one of the most magnificent in the world， due to the “hanging valleys” left by the formation of the Yosemite Valley itself， and the wet climate characteristic of the park. As a result， 5 of the Yosemite Valley，s falls are among the 10 highest waterfalls on earth.
Perhaps the most famous of the waterfalls is the double waterfall known as Yosemite Falls， which falls a total of 2，425 feet. There are three separate sections - the Upper Falls (1，430 feet)， a middle falls (675 feet)， and the lower section (320 feet).The photograph below provides a view of the upper and lower section of the waterfall.
Yosemite Falls is so high that it is equivalentequivalent adj.相等的， 相当的， 同意义的 n.等价物， 相等物 to more than 12 Niagra Falls one on top of another. Counting the total drop of all 3 sections， it is surpassed in height only by Angel Falls in Venezuela.
Yosemite Falls is especially spectacular in the winter when the cliffs are covered by snow， ice， and frost.
Yellowstone National Park黄石国家公园
1872年，美国总统格兰特签字同意在怀俄明州开辟黄石国家公园。于是美国第一个、也是世界上第一个由政府主持开辟的国家公园诞生了。目前美国有36所国家公园，黄石国家公园是其中最大最着名的一个。它地处怀俄明州西北角，并延伸至爱达荷与蒙大拿两个州，面积达8800平方公里。在这个庞大的公园里，游客可驾车长驱直入，大饱眼福，尽兴而归。
黄石国家公园最使游客感兴趣的是数以千计的温泉、喷泉和一座座泥山。山谷里，温热的泉水喷涌而出。时疾时息，极富特色，形成自然界中一大奇观。在数不胜数的大小喷泉中，以老忠实喷泉最为着名。它不以其大招徕游客，也不以其美博人欢心，而是以它始终如一的忠实受到世人的称颂。老忠实喷泉每隔61到67分钟喷出一次，每次历时约4分钟，喷得最高最美之时是前20秒，每次共喷出热水约1万加仑，高度达40~50米，水温摄氏93度。经冬历夏，老忠实喷泉都这样按照一定的规律不竭地喷涌着，遂得“老忠实”这样的美名。人们来到黄石公园，必以到老忠实喷泉一睹为快。但见它不喷则已，一喷则如万马奔腾，更兼在阳光辉映下，水蒸气闪出七彩颜色，蔚为壮观，谁人能不发出赞叹之声。
黄石国家公园还有一个引人注目的地方，就是位于公园中心的黄石湖。它是全国最大的山湖，又是密西西比河的发源地。黄石湖水清见底，湖水经过一个缺口流入黄石大峡谷，呼啸而下，形成着名的黄石大瀑布。
黄石国家公园以熊为象征。园内约有200多头黑熊，100多头灰熊，在路边常常可以看到一只大熊带着一两只小熊，阻住游人的汽车伸手乞食，那种滑稽的样子，煞是逗人爱怜。可惜的是，熊的数量日渐减少，政府不得不采取措施对它们严加保护。此外，园内还有各种野生动物。据统计有1万多头大角鹿、1000头麋鹿、600多头野牛。较小的飞禽走兽，更是种类繁多，处处可见，给游客增添了不少情趣。
Among national parks Yellowstone is first in may ways. It is the first national park in the world， the example on which parks everywhere are modeled. It is the largest park in the lower 48 states， larger than the states of Delaware and Rhode Island combined. It has some of the most famous park features， such as Old Faithful， the Grand Canyon of the Yellowstone， and freely roaming herds of buffalo. It also includes the nation，s largest wildlife preserve， an enormous lake， the Continental Divide， some 10，000 hydrothermal features， and over 1，000 miles of trails. And its diversity of attractions is a match for any location on the planet.
Yellowstone is one of the most popular of the national parks， particularly in the western part of the country. Nearly three million people visit the park each year， and over 60 million have visited it since 1872.
Park History
The Yellowstone area has a a wild geologic history. Over 600，000 years ago the central portion of the park exploded and collapsed， leaving a smoldering caldera 28 by 47 miles in size. The hydrothermal features in the park are continuing evidence of the powerful effect of geological forces.
Evidence indicates that the area was used by hunters for at least 5000 years. Prior to the arrival of American explorers Indian tribestribe n.部落， 部族 used the area on a steady basis as a source of food， weapons， and the obsidian found in the Yellowstone area. The Crow， Blackfoot， Bannock， and Shoshone tribes were frequent inhabitants.