| 1 | Be alert when driving. | |
| 2 | The cat is alert to every sound and movement. | |
| 3 | It may serve you, however, to be aware of consequences. | |
| 4 | The coastal guard kept a watchful eye on the black spot that had appeared out at sea. | |
| 5 | Be alert: if you feel ill, talk to someone about your worries. |