Many difficulties have as a result of the change over to a new type of fuel.
A. risen
B. raised
C. arisen
D. arrived
网友回答
A. risen
B. raised
(答案→)C. arisen
D. arrived
解析：risen上升，不及物动词，raised举起，升起，及物动词，arisen产生，出现，arrived到达，句意：由于一种新燃料改变的结果，许多困难出现了。故选C。