the sound of knocking (as on a door or in an engine or bearing);
\\\"the knocking grew louder\\\"
造句
用作名詞(n.)
A war came knocking on your door. 一個(gè)戰(zhàn)爭(zhēng)受到在你的門上爆震音的影響。
(vbl.)
They found that knocking out the gene in fetal mice whose hematopoietic systems had already formed caused hematopoietic stem cells to disappear. 他們發(fā)現(xiàn)擊昏已經(jīng)形成造血系統(tǒng)的胚胎小鼠的基因會(huì)引起造血干細(xì)胞的消失。