| 1 | They were constantly on the alert not to be taken by surprise. | |
| 2 | This commitment will ensure that our arsenal remains ready. | |
| 3 | The sudden environmental pollution accident has the uncertainty, therefore re- quests to monitor the preparatory work to be ever prepared; | |
| 4 | A hospital should work out a pre-scheme for emergence response to sudden medical incidents based on the guidelines of " prevention first" and "always be on the alert". | |
| 5 | For a half century, America defended our own freedom by standing watch on distant borders. |