系列: succession; series; bank; set; set family; train 短语和例子一系列的灾难 a succession of disasters; 一系列的问题 a series of problems; 一系列政策 a whole set of policies; 系列试题 test series; 运载系列 vehicle series; 系
普通螺纹: common threadplain threadregular screw threadsstrthd