题目内容：

The Rio Grande

Although not the longest in America, the Rio Grande is one of the most important. But, unlike other significant rivers, it is not used for shipping. In fact, ocean-going ships cannot sail on its water. 1. Since 1846, it has been the official border of Texas and Mexico.

Rio Grande Geography

The Rio Grande is either the fourth or fifth longest river system in North America. It all depends on how it is measured. 2. and these course movements can cause it to be longer or shorter. At its last official measure, the Rio Grande clocked in at 1896 miles. The river starts in Colorado and extends downward to the Gulf of Mexico. 3. Not only does the river extend south, but it also starts in the mountains and gets lower and lower in altitude as it extends to the Gulf.

The Rio Grande Today

4. Sadly, much of the water has been used up and parts of the river are most dry! This is because people take more water from the river than the river can get back from rain and other sources. Experts are working to correct this, though, with the hopes of restoring the river to its past strength.

Today, the river is important as a source of water for Texas and Mexicans. 5. Though borders like the Rio Grande separate nations, they are also shared spaces. The Rio Grande is therefore a symbol of friendship and peace between two peoples.

A. Usually, it is measured by length.

B. Downward is the best way of describing it too.

C. What makes the Rio Grande so important is its location.

D. Because the river twists so much, it occasionally changes course.

E. The Rio Grande today is mostly used as a source of drinking water.

F. More importantly, it is a symbol of cooperation between two nations.

G. Today, the Rio Grande is the destination of tourists from all over the world.