Happy swallow
Yitangyanque, a Chinese idiom, Pinyin is y í t á ngy à nqu è, which means that birds live in comfortable halls. It refers to a person who is in danger and doesn't know it. It comes from Cheng dengji's "learning from qionglin in childhood".
The origin of Idioms
The fourth volume of Cheng dengji's "learning from qionglin in childhood" is: "a bird in a pleasant house knows no aftereffect; a chicken in a jar is widely seen.
Idiom usage
As an object or attribute; used in figurative sentences
Happy swallow
provide each other with assistance - gòng wéi chún chǐ
hear readily without comprehending what is heard - ěr shí zhī lùn
compasses , set square , spirit level and plumb line - guī jǔ zhǔn shéng