5N-COUNT [usually plural]空包弹Blanks are gun cartridges which contain explosive but do not contain a bullet, so that they cause no harm when the gun is fired. 空包弹
7PHRASE 一无所获;扑空 If you draw a blank when you are looking for someone or something, you do not succeed in finding them. 一无所获;扑空 [informal]
They drew a blank in their search for the driver.
他们四处寻找那个司机,但一无所获。
8PHRASE (脑子)突然一片空白 If your mind goes blank, you are suddenly unable to think of anything appropriate to say, for example in reply to a question. (脑子)突然一片空白