听力原文：

B: Riley, do you know what the largest plain in area is in the world?

G: The Amazon Plain. It’s more than 5.6 million square kilometers.

B: What about the Northeast China Plain?

G: It’s the largest plain in China.

B: Which is the coldest of all the plains?

G: The Siberian Plain. Its average temperature was -45 degrees and the lowest was -71 degrees.

B: It’s so cold. Which country has the longest coastline in the world?

G: Canada. The Canadian coastline is 202,080 kilometers long.

B: I thought Indonesia’s coastline was the longest of all the countries.

G: Indonesia comes in second, with 54,716 kilometers of coastline.

B: Which country has the largest population?

G: China. The population is about 1.4 billion.

B: How long is the Yellow River?

G: It’s 5,464 kilometers long. The Yellow River is the second longest in China.

B: What else in China ranks first in the world?

G: Hulunbuir Grassland. It’s the best quality grassland.

答案：2. B 3. C