邀请函的英文怎么说

邀请函的英文：
invitation

Entry to this competition is by invitation only.
此次竞赛的参赛只凭邀请函。

Nobody in the office had received an invitation to the party.
在办公室里没有人收到邀请函去参加这个宴会。

Whomever you invite will be welcome.
你邀请的任何人都将受欢迎。

He was upset at not being invited.
人家没邀请他，他很不痛快.

A Bad padlock invites a picklock
坏锁招人撬

Entry to this competition is by invitation only.
此次竞赛的参赛只凭邀请函。

She was favored with an invitation.
她受到了邀请。