StringBuffer s = newStringBuffer("happynewyear");s1 = s.substring(5,8);System.out.println(s1);程序输出结果为（） A: ynew B: new C: ewy D: happy

  某溶液中含有 [tex=3.929x1.214]UGhJl/J6jn9ySByB4+ILRojri7cmoZgpvGy+9f5fuEQ=[/tex] 和 [tex=3.429x1.214]4pYEdQ6bu7+lUbnJYqE9eudWFs5dwx4S1yCToXlKWsFa8Rvf9lF33mZmfjqMYATC[/tex] 其浓度均为[tex=6.0x1.429]sA8EhWjVHqevI3zl03/CUQIqrgCGscI0T5ipyATkC4lKJYbxPkFOCmjsPBbnpuCa[/tex]向该溶液中逐滴加入 [tex=5.786x1.214]sA8EhWjVHqevI3zl03/CUQIqrgCGscI0T5ipyATkC4k0uZ/rOAHVauWtmtEH1PVJ[/tex] 的 [tex=3.143x1.286]BKrsxVq4bENQKOMraHT6YKvgKxRD4z8tM4Uy065DU4I=[/tex] 溶液时，最先和最后沉淀的是(  )   ( 已知: [tex=34.786x1.571]wo2uiZ609QyfdfLdTANh2qBRbuNLyPJnRoiwsrdSDwyEiOJcJ/9Gp5xP8GpBCa4LqP4dc/fut3Y1N3nmNnlRUkNkgaYJh/EONBkDMJHZJAgD5KVDRu9+Pphgw57mg8O3wCpg4WlX4TBtm++XY2GZU0zPnXkDh7Bz/6aoKmFFAF9uNAdjUoCgcwPDTyjBfLIqu/BpISvmxw4697DE5PlYJjUIhj42I3kmwx+AFONMRt5nu476bQnrAM7x6a9+F5g44cZ7/oygo+d+hfoTKhmkPy//JsmD4lUsUa+w0Bh/EWY=[/tex] 未知类型：{'options': ['[tex=2.357x1.214]AGb9sn28cW73q3/3tjcPZA==[/tex] 和 [tex=3.857x1.286]sYs5YCnjopozxoTwTKPDa0749nWi0jz3N4LHKMpNNsLOz0p/Ta9wpbi+oOE0vzH1[/tex]', '\xa0[tex=3.857x1.286]sYs5YCnjopozxoTwTKPDa0749nWi0jz3N4LHKMpNNsLOz0p/Ta9wpbi+oOE0vzH1[/tex]\xa0和\xa0[tex=2.286x1.214]Lj78Ya7rjo5rBPmDVw9G8w==[/tex]', '[tex=2.357x1.214]AGb9sn28cW73q3/3tjcPZA==[/tex]和\xa0[tex=2.286x1.214]Lj78Ya7rjo5rBPmDVw9G8w==[/tex]', '一齐沉淀'], 'type': 102}