Whistling means blowing or as if blowing a flute.

Example: Then the train stops whistling, slows down and stops with a sigh.

The origin of whistle

The air defense alarm sounded and the whistle sounded from 9. 18. The purpose of whistling is to remind us not to forget the national humiliation.

Air defense warning is an important part of urban air defense engineering, which is usually used for disaster prediction and emergency notification in emergency rescue and disaster relief and sudden accidents. Used for civil air defense in wartime is the basic means for people's governments at all levels to carry out civil air defense command and organize personnel evacuation.

The function of whistle

Whistling is a sign of conveying information when it has special significance. For example, trains need to whistle to inform relevant departments or personnel when entering or leaving the platform. For example, the car horn is also a message to remind others to pay attention to safety, and it also indicates whether the car is going forward or backward. Sometimes it is necessary to whistle in memory of someone to express the memory of something or to mourn for someone!

1, warning

For example, when a train stops or starts, it should whistle to warn people.

Step 2 remind the bill

Police cars, fire engines, ambulances, etc. When performing special tasks, there are special flutes for everyone to know. So as to avoid vehicles in advance and improve work efficiency.

Step 3 Deterrence

For example, when a police car goes out, it will whistle to give an alarm, which will play a demonstration role, make the suspects feel scared, and let them know that the law will soon punish them and make them stop doing wrong.

Step 4 mourn

Throughout the country, horns are sounded on special anniversaries, such as the Wenchuan earthquake (5. 12), to show commemoration and mourning.