题目

It was the first time he felt he had achieved something by ______.A.him B.himself C.his D.he 答案：【答案】B【解析】句意：这是他第一次感到自己已经取得了一些成就。考查反身代词。A. him他，宾格；B. himself他自己，反身代词；C. his他的，物主代词；D. he他，主格。短语by oneself：独自，自己；故选B。函数的最小正周期是     ．