Did you mean: study shidu shudi shedu shoudu sudu shed shadu ?
| 熟读 | shú dú | to read and reread sth until one is familiar with it |
| 书蠹 | shū dù | bookworm (literal and figurative) / book louse / pedant |
| 书牍 | shū dú | letter / wooden writing strips (arch.) / general term for letters and documents |
| 数独 | shù dú | sudoku (puzzle game) |