TOEFL Reading: ETS-TOEFL阅读机经 - 347JDE7LH35485TBL$

Why does the author mention that "Farmland owners turned part of their land into pasture land for sheep?" A. To explain why the younger sons of land owners had to leave the family land and find other jobs B. To provide an example of a way in which large farms were eager to improve their business C. To explain how the practice of primogeniture worked D. To describe a strategy land owners used to give their lands from being subdivided.