| to explain the ideas | 17 | purpose |
| often | 14 | temporal |
| in their research | 14 | location |
| student → use → book | 277 |
| student → use → textbook | 166 |
| student → study → textbook | 14 |
| negative | neutral | positive |
| 0.108 | 0.647 | 0.245 |
| Raw frequency | 457 |
| Normalized frequency | 0.513 |
| Modifier score | 0.636 |
| Perplexity | 470.580 |