问题
选择题
Low-carbon lifestyle is of great benefit to improve the world environment, but the problem is difficult to _________．
A．solve
B．be solved
C．solve with
D．solving
答案
答案：A
考查固定句型：sb/sth is+adj+to do“某人/某物做…是如何的“，这个句型是主动表被动，句意是：低碳生活方式对提高世界环境很有益，但这个问题很难解决。选A。