单项选择题

The Para 5 mainly discusses ______.

A．how animal wastes enriched land
B．how plant roots protected the land
C．how humus becomes useful
D．how a forest creates its own soil and protects the watershed
<上一题 目录 下一题>
热门 试题

单项选择题
In this sentence In short, land is fragile. (Line. 1, Para. 7), what does the word fragile mean
A．Very poor.
B．Rich.
C．Taken.
D．Easily destroyed.
单项选择题
Each of these land uses swallows up precious space, swallows up means ______.
A．occupies
B．gives up
C．disappears
D．takes completely
相关试题