49.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。