题目

__________you eat the correct foods ________ be able to keep fit and stay healthy.      A. Only if ; will you    B. Only if ; you will    C. Unless; will you   D. Unless ; can you 答案：A有两组扑克牌各三张，牌面数字分别都是1，2，3，随意从每组中个抽出一张．数字和是偶数的概率是 ________．