formal invitation

基本解释

A: So far as I know, we haven't received any formal invitation, therefore I can not predict or judge whether to accept or not.
答：根據我目前掌握的情況，我們還沒有收到任何正式的邀請，無法預測或判斷是否會接受。
www.fmprc.gov.cn
"Each student will receive a formal invitation to which he will have to respond in a written formal manner and not by email, text message or phone," the spokesman said.
這位發言人說：“每名學生都會收到一封正式邀請函，而他們必須以正式的書麪形式答複，不得發電子郵件、發短信或打電話。”
In January he was dispatched to Libya to deliver a formal invitation for Muammar Qaddafi to visit Sri Lanka, to improve the “strong personal relationship” between the two country’s leaders.
一月，爲了增強兩國領導人之間“深厚的人際關系”，他奉命到利比亞正式邀請穆阿邁爾·卡紥菲縂統到斯裡蘭卡訪問。

"So far,at this date and time, I have no information if we have received any formal invitation from the organizers of that Hague summit,".
"But if we receive that formal invitation, we would consider that positively."

Such a formal invitation to foreign workers has not been known since the first Turks, then and still needed, but now so often unwelcome, arrived in the 1960s.
ECONOMIST: Europe’s migrants