TOEFL Reading: ETS-TOEFL阅读机经 - 7XDRCUPX570G343NL$

Which of the following can be inferred from paragraph 1 about the intensive agricultural methods of the Maya? A. They helped the Maya overcome short-term fluctuations in the climate. B. They could not supply all of the food required for the growth of Mayan cities. C. They strained the environment more than the Maya's previous farming techniques did. D. They were invented by the Maya to help them grow new kinds of crops.