Many developed countries have agreed to help the less developed ones but it remains whether they will take action or not.
A. to see
B. to be seen
C. seeing
D. seen
网友回答
A. to see
(答案→)B. to be seen
C. seeing
D. seen
解析：句意：很多发达国家已经同意帮助不太发达的国家，但是是否他们会采取行动还要拭目以待。Remain后面可以接不定式，表示将要发生的动作，而且it和see是被动关系，用不定式的被动，所以选B。