The function of this sentence is to express optimism about life and confidence in the future, and encourage people not to give up easily. Secondly, take dusk and shadows as metaphors to convey the attitude towards adversity and setbacks, that is, no matter how many difficulties and setbacks you encounter, you must be tenacious and unyielding. Finally, encourage people to face their inner thoughts and feelings bravely, and don't compromise and give up their beliefs easily.

No matter how long the shadow of dusk is painted, a poem in the Indian poet Tagore's Birds means that no matter how long the shadow of dusk is painted, don't give up hope and efforts. The meaning of this sentence is to convey that it is very important to maintain a positive and optimistic attitude in the face of setbacks and difficulties in life, because adversity and even failure are often accompanied by dark and desperate ideology. When we can't control and change the development trend of things, what we can control is our attitude and behavior choice. This sentence inspired our courage and determination not to yield in the face of setbacks, and encouraged us to persist in and pursue our original beliefs.