Yellow - be on the alert.
Every country that advocates peace must be on the alert.
Drivers must be on the alert for traffic signals.
Police warned the public to be on the alert for suspected terrorists.
Police are warning the public to be on the alert for suspicious packages.
They want to be on the alert for similar buying opportunities.
The police of Marseilles will be on the alert by land, whilst the governor pursues me by sea.
We have been worried about the possibility of war and have had to be on the alert every year.
When you back out of your driveway or leave your garage, be on the alert for children who are walking or bicycling to school.
We are therefore campaigning for authors, researchers and editors to be on the alert for plagiarism and to work against cultural misunderstandings.
Currently, first, the BRICs should be on the alert that hostile powers in developed countries may make mischief between them under the cover of ideology and history-made problems;
Considering the fact that the patient's heart,lungs,kidneys and Brain functions have remained poor, one should be on the alert for an accident that might recur at any time.
