In this section, you will hear one passage. At the end of the passage, you will hear four questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D).A、These discoveries took about 10 years of time.
B、These discoveries were made in five different countries.
C、Only animals have been discovered.
D、Experts were worried about the discoveries.