"Empty pair" sentence: It means that although Baoyu and Baochai are married, they lack real love between husband and wife. The nobleman in the mountains is better than Baochai, which shows that he is lofty and clean. Snow, homophonic with "snow", refers to Baochai and her indifference.
The phrase "outside world": "outside world fairy" means that Lin Daiyu was originally a crimson pearl fairy. Hey, beauty. The lonely forest indicates the lonely death of Daiyu. After this sentence was written, Jia Baoyu kept thinking about Lin Daiyu. He loves Lin Daiyu, so he can't express himself.
Extended data:
Baoyu's Poems in A Dream of Red Mansions;
1, one is Xianpa in Yuen Long, and the other is flawless jade. If there is no strange fate, I will meet him again in this life; You said that fate is strange, how can your heart be empty! One is futile, the other is alarmist; One is the moon in the water, and the other is the flower in the mirror.
I am used to laughing at your stupidity, and I was stunned by the snow. After the Lantern Festival, it's time to put out the smoke.
References:
A lifetime of mistakes (Sanqu in Cao Xueqin's Dream of Red Mansions) _ Baidu Encyclopedia