invitation是可数名词，复数形式：invitations。例句：Have you ordered the wedding invitations yet?你订制婚礼请帖了吗？
invitations例句
1、She had sent out well over four hundred invitations that afternoon.
那天下午她发出了远远不止400份请柬。
2、I learned long ago to avoid these invitations
我很早就学会怎样躲开这种邀请了。
3、Hundreds of invitations are being sent out this week.
本周将寄出数百份请柬。
invitation例句
1、He will not come without your invitation.
没有你的请柬他是不会来的。
2、If I were you, I should refuse his invitation.
如果我是你的话，我会拒绝他的邀请。
3、If I were you, I should accept the invitation.
如果我是你，我会接受这个邀请。