at sb’s invitation;on(or upon)invitation 中國代表團～出席大會，感到榮幸和愉快。The Chinese Delegation is honored (or privileged) and pleased (or delighted) to be invited to the Conference/～出席國宴be invited to the state banquet;attend the state banquet upon invitation/～來中國訪問come to visit China upon invitation/～派代表團參加國慶活動send a delegation to attend the national day celebrations at the invitation (of the Chinese Government)