望梅止渴 [wàng méi zhǐ kě]
Literally, this idiomatic expression means that one' s eyes look at the cherry grove and drool, satisfying one' s thirst with saliva. It is a metaphor to indicate being relieved of unrealistic and empty thoughts.
Story related to expression:
At the end of the Eastern Han Dynasty, Cao Cao (a famous military and political figure of the Eastern Han Dynasty) led his troops to defeat Zhang Xiu, who was installed in Wancheng. It was already noon, and the sun was scorching. The soldiers were carrying heavy weapons and were completely drenched in sweat, hot and thirsty, which made it very uncomfortable and caused serious trouble on the march.
When Cao Cao saw the soldiers licking their dry lips and trudging along, he became very anxious. He ordered the men to rest where they were and sent them to fetch water. After a while, all the men returned with empty buckets. It turned out that the area was a desert, with no rivers or mountain springs, so there was no water to be found. Cao Cao ordered the soldiers to dig a well on the spot, but after a long time, they could not draw a drop of water.
Cao Cao thought to himself that the situation was serious and that if he stayed here too long, more men would not be able to hold out. After thinking for a moment, Cao Cao aimed his horse whip fiercely at the hill ahead and said loudly to the soldiers under his command, "I know this place, on the hill ahead there will be a large and exuberant poplar plum grove, once there, each of you can enjoy the plums as you wish."
As soon as the soldiers heard about the plums, they naturally imagined the sour taste and therefore drooled, and suddenly did not feel so thirsty. Cao Cao immediately ordered the troops to march and, after a while, succeeded in bringing them to a water source, where they drank the water with great pleasure and continued the march with renewed vigor.
Sentence with 望梅止渴：
Throughout the entire departure from the desert, the general had motivated the group by looking at the plum tree to quench their thirst.
He can't afford to buy a house, so he has to watch ads every day to console himself.