Forests cover nearly ______ of the United States, and they yield

Forests cover nearly ______ of the United States, and they yield many valuable products.
A、a fourth
B、a third
C、half
D、two thirds
【正确答案】：B
【题目解析】：森林覆盖了美国近三分之一的面积，并产出许多有价值的产品。