2.下列各式中运算正确的是( )
0 278904 278912 278918 278922 278928 278930 278934 278940 278942 278948 278954 278958 278960 278964 278970 278972 278978 278982 278984 278988 278990 278994 278996 278998 278999 279000 279002 279003 279004 279006 279008 279012 279014 279018 279020 279024 279030 279032 279038 279042 279044 279048 279054 279060 279062 279068 279072 279074 279080 279084 279090 279098 366461
| A. | 3m+2=5m | B. | 2x2-x2=2 | C. | ab-ab=0 | D. | y+y+y=y3 |