A-A+
29． Why are green plants and grass helpful？A．
问题详情
29． Why are green plants and grass helpful？
A． Because they can hold the water．
B． Because they can stop the wind from blowing the earth away．
C． Because they can keep the earth wet．
D．All the above．
参考答案
正确答案：D
29.D【解析】从第二段可知A、B、C三项内容全都包括，故选D。
