六级练习2015.03.28
[audio]http://sound.yywz123.com/tingbbs/cet6/cet620150328.mp3[/audio]Farmers usually use plows to prepare their fields for planting crops. Plows cut into the ground, and lift up weeds, and other unwanted plants. However, plowing is blamed for causing severe damage to top soil by (1)_______________________________. Many farmers in South Asia are now trying a process called Low Till Farming. (2)____________________. In this method of farming seeds and fertilizer are put into the soil through small cuts made in the surface of the ground. Low Till Agriculture leaves much or all the soil and remains of plants on the ground. (3)____________________________. They take in rain and allow it to flow into the soil instead of running off.
**** Hidden Message *****
页:
[1]