PHRASAL VERB 大量投寄；成批邮寄；群发 If someone mails out things such as letters, leaflets, or bills, they send them to a large number of people at the same time. 大量投寄；成批邮寄；群发 [mainly US] [Also VERB n PREPOSITION]
This week, the company mailed out its annual report. [VERBPREP. noun]