Meaning of yī xià zi:
yī xià zi
一下子
Adverb
in a short while; all at once; all of a sudden
Tiān shàng de wū yún yī xià zi xiāo shī le.
天上的乌云一下子消失了。
The clouds in the sky disappeared in a short while.
Tā yī xià zi jiù jiě jué le zhè gè wèn tí.
他一下子就解决了这个问题。
He solved the problem all at once.
Tā yī xià zi xiào le qǐ lái.
他一下子笑了起来。
He suddenly started laughing.