新东方网英语四级频道为备考英语四级的同学整理了英语四级词汇讲解及考点归纳，希望可以为大家带来帮助，一起来学习一下吧。
I was under the impression that the tickets were sold out a long time ago.
四级词汇讲解:
be under the impression that…意为“认为，觉得”，该种表达不常见，因此是本句的难点。其实它相当于think或者have the feeling that……。如:
※ I was under the impression that he was kind.我的印象中他挺善良的。
※ I'm under the impression that language is complex.我觉得语言挺复杂的。
※ I am under the impression that it will rain in the afternoon.我觉得下午会下雨。
From:https://www.zgghmh.com/CET-4/20004256.asp