Read the following conversation and answer the question. M: Isn't the Changjiang River twenty-five thousand kilometres long? W: Oh, no, it's not as long as that. It's about a quarter the length you said. Question: How long is the Changjiang River? - About 6000 km. - About 5000 km. - About 4000 km.
The answer to this question is:
About 6000 km.