Fill the words into the blanks. only , ways, water , however, yet, rain ,countries, do, dry, another, introduce high, often, plants, reasons, take care of , possible, centuries, grown, included Mexico , the largest nation in the region, is a good example of life in Middle America. Although Mexico is a large country, 1 12 percent of its land is good for farming. 2 40 percent is good grassland. The rest of the land is hills and mountains, 3 plateaus ( 高原 ), or wet coastal regions. The mountains are too 4 to farm. The high plateau in the middle of Mexico would be good farmland if it had more 5 The coastal areas receive so much 6 that the land 7 becomes waterlogged( 浸满水的 ). For all of these 8 , Mexicans must 9 the good farmland they have. 10 good farming has not always been 11 in Mexico . For many 12 , Mexican farmers had 13 traditional crops. These 14 com, beans, and squash ( 南瓜 ). 15 , when the Spanish arrived in the 1500’s, they tried to 16 new ideas. They thought new 17 such as onions, turnips, sugarcane, and bananas would 18 well in warm tropical ( 热带的 ) 19 . But the Mexicans wished to continue with their old 20 .