(一)作答之道(接上期)方法五:分分组,看规律。方法是,对数列进行分组,两两分组或三三分组,看有什么规律,根据这个规律来选择正确答案。运用这种方法,数列所给的项必须足够多。比如,1,1,8,16,7,21,4,16,2,()A.10 B.20C.30 D.40作答此题,要将这个数列两两分组,发现两两分组后两项比值分别是1,1/2,1/3,1/4……下一项为 (A) answer the road (access period) Method five: sub-group, see the law. Method is to group the number of pairs, twos or three or three groups, to see what the law, according to this law to choose the correct answer. Using this method, the number of items given must be sufficient. For example, 1,1,8,16,7,21,4,16,2, () A.10 B.20C.30 D.40 To answer this question, this series should be divided into two groups and found after two groups The two ratios are 1,1 / 2,1 / 3,1 / 4 ...... The next one is