To make members of a team perform better，the trainer first of all has to know their                and weaknesses．

A.strengths

B.benefits

C.techniques

D.values

答案及解析： A

解析：

strengths and weaknesses优点和缺点, benefit n.益处, 好处；

technique n.技巧, 手法, 技术；

value n.价值, 价格。