Ships sailing at sea need a lighthouse to indicate the direction, otherwise they may run aground or sink on the rocks.

There are too many such accidents in the history of navigation.

This tragedy has brought great losses to human life and property, and also taught people a profound lesson.

This is not the case on the road of life.

If you want to do something, you must have a correct outlook on life as a guide. Otherwise, you will do nothing, waste time and even go astray.

Delete sentences ② and ③.