首先我们来看下send out、send off的大致意思
send out：词性为动词短语，send out指从一个地点或源头发出或寄出东西，可以是物品、信件、通知等。
send off：词性为动词短语，send off指送行或派遣某人离开某个地方，也可以指发出信件等。
通过下面的图我们了解下send out、send off的含义、发音和用法
接下来我们讲解几个用例，希望这些用例可以加深您的理解
send out：
The company sends out a daily newsletter.
(公司每天都会发送新闻简报。)
They are sending out invitations.
(他们正在发送邀请函。)
The government has sent out reinforcements to the disaster area.
(政府已经派遣援军前往灾区。)
She is sending out birthday gifts to her friends.
(她正在寄送生日礼物给朋友。)
I will send out your package tomorrow morning.
(我将在明天早上寄出你的包裹。)
The letter has been sent out by the post office.
(这封信件已经被邮局寄出。)
send off：
Our whole family went to the airport to send him off.
(我们全家都去机场送他离开。)
They sent off the teacher at yesterday's ceremony.
(他们在昨天的仪式上送别了老师。)
She went back to her room after sending off the guests.
(她送走了客人后回到了房间。)
They have just sent off a team to carry out the mission.
(他们刚刚派遣一支队伍去执行任务。)
Please send off this letter before tomorrow morning.
(请在明天早上前寄出这封信。)
They sent off a rescue team to help us.
(他们派出救援队来帮助我们。)