We should unite, for no country can solve the problem of the pig flu.
A. alone；for
B. lonely; because
C. only; since
D. simply; as
网友回答
(答案→)A. alone；for
B. lonely; because
C. only; since
D. simply; as
解析：考查副词和表示原因的连词的辨析。句意：没有任何一个国家独自可以解决猪流感问题。Alone adj.独自，单独；for补充说明原因符合句子。