They each ______strengths and weaknesses; it is proposed that th

They each ______strengths and weaknesses; it is proposed that they be combined.
A、are
B、has
C、have
D、is
【正确答案】：C
【题目解析】：Each用于单数名词前，谓语动词用单数，用于复数名词后，谓语动词用复数形式。Each of，each one of后接复数名词或代词，但谓语动词常用单数形式。