9. It takes a deft balance between savings discipline, investment knowledge, risk taking, luck, and time to raise a million dollars through investments.
(A) It takes a deft balance between
(B) Deft balancing is needed between
(C) Deftly balanced, it takes
(D) It takes a deft balance of
(E) A deft balance is what one needs among
答案为D，我做的时候选了A。我查了以前的帖子，不过好象没有很明确结果，所以想再问一边。为什么不能用BETWEEN。请NN指教。 | 
