They wave when someone says 'bye-bye';

有人说“bye-bye”时，他们会摆摆手；

youdao

Mommy's going to work. Wave bye-bye.

妈妈要上班了。宝贝，来挥挥手说再见。

youdao

Mommy's going to work. Wave bye-bye.

妈妈要上班了。宝贝，来挥挥手说再见。

youdao