| 知识点（KP） | 南京大学202x | 美国英语新闻 |
| amn. + back | 30.33 | 384.16 |
| von. + back | 57.30 | 252.97 |
| back | 4374.80 | 12518.32 |
| back + amn. | 70.78 | 491.92 |
| back + von. | 111.22 | 218.59 |
| back/a | 97.74 | 559.74 |
| back/ajp | 80.89 | 533.49 |
| 形容词 back | 94.37 | 543.79 |
| back/avp | 819.01 | 3959.53 |
| 副词 back | 832.49 | 4061.81 |
| back/bit | 97.74 | 478.94 |
| back/d | 3643.42 | 9683.26 |
| back/lex | 4421.99 | 13458.67 |
| back/n | 279.74 | 1726.72 |
| back/np | 16.85 | 35.95 |
| 名词 back | 141.56 | 955.45 |
| back/pos | 4438.84 | 13508.10 |
| back/ske | 80.89 | 323.98 |
| back/v | 417.93 | 1538.38 |
| back/vp | 3.37 | 11.37 |
| 动词 back | 40.45 | 152.75 |