| 1 | The company implemented a rigorous quality control system. | |
| 2 | An impartial evaluation system is the foundation of ensuring educational fairness. | |
| 3 | The political system of this country is undergoing great upheaval. | |
| 4 | The army is an important component of the contemporary national security system. | |
| 5 | He gradually formed his own ideology through continuous learning. |