| 1 | The oldest kind of computer is the abacus. | |
| 2 | Why is the abacus such an effective teaching device? | |
| 3 | In English we call it an abacus. | |
| 4 | The clerk reckoned the expenditure last week with an abacus. | |
| 5 | Because the abacus is a daily-use device made from wood, few of them have survived. |
Copyright © Purple Culture Co., Ltd. 2001 - 2026. All right reserved.
