In this section, you will hear several passages.
Listen to the passages carefully and then answer the questions that
follow.
Questions 11 to 13 are based on the
following passage. At the end of the passage, you will be given 15 seconds to
answer the questions. Now, listen to the
passage.
What does the passage mainly discuss
A．How canals are constructed. B．Common types of canal boats and barges. C．The world’s largest canals. D．How canals are used and classified.