An invasive creeping weed native to the Mediterranean region, Cirsium arvense has been present in Yellowstone National Park at least since the nineteen century. Because of its extensive root system, the plant defies attempts to (i)_____ it by normal methods, and consequently, park officials have (ii)_____ efforts to do so. Warming temperature have also (iii)_____ of the thistle’s fortune.
答案：A,D,G