问题
选择题
People have planted a great many trees in order to ____wind and sand in the desert.
A．hold down
B．hold up
C．hold back
D．hold out
答案
C
hold down压制，限制；hold up推迟，耽搁；hold back阻挡，抑制；hold out提供，提出。句意：人们种了大量的树，为了阴挡风和沙尘。由此可知答案为C项。
伸肌、趾伸肌