| 1 | The roof fell down. | |
| 2 | The largest risk in coal mining is the collapse of the mine. | |
| 3 | When we don't have love, it feels as though the world around us is crumbling down. | |
| 4 | The tonus has given way, and this is left subjectively as lifelessness, moroseness, and depression. | |
| 5 | China wants to avoid regime collapse in its neighbor to prevent a flood of refugees across their 1,415-kilometer (880- mile) border. |