(a) [Ipr, Tn, Tn.pr, Tn.p] strike (sth) deliberately and violently, often in order to make a loud noise 故意猛砸（常为产生巨响）: He was banging on the door with his fist. 他用拳头砸门. * I banged the door. 我砰的一声关上了门. * She banged her fist on the table. 她用拳头猛捶桌子. * I banged the box down on the floor. 我砰的一声把盒子摔在地板上. (b) [I, Ip, Tn, Tn.p] ~ (sth) (down, to, etc) close with a loud noise 砰的一声关上: A door was banging somewhere, ie opening and closing noisily. 不知哪里有扇门砰砰作响（开门和关门的响声）. * Don't bang the door! 不要砰砰地关门! * He banged the lid down. 他把盖子砰的一声关上了. 
(a) [Tn, Tn.pr] hit violently and often unintentionally 猛击（常为无心地）: She tripped and banged her knee on the desk. 她绊倒了, 膝盖猛磕在书桌上. (b) [Ipr] ~ into sb/sth collide with sb/sth violently 猛撞着某人[某物]: He ran round the corner and banged straight into a lamp-post. 他跑过拐角处时迎面撞在灯柱上. 
[I, Ip] make a loud noise 发巨响: The fireworks banged impressively. 烟火响声震天. 
(phr v) bang about/around move around noisily 发出响声地动来动去: We could hear the children banging about upstairs. 我们可以听见孩子们在楼上乒乒乓乓地跑来跑去. bang away (a) (infml 口) work hard, esp using a typewriter 努力工作（尤指打字）. (b) (sl 俚) have vigorous sexual intercourse 纵情性交. (c) (infml 口) fire continuously 不断射击: We were banging away at the enemy. 我们乒乒乓乓向敌人射击. * The guns banged away all day. 枪炮声整天响个不停.NOTE ON USAGE 用法:
1 Knock means hitting something with a clear, sharp sound. *knock意为敲击某物而发出清脆的声音. One may knock to signal one's presence to others 可用敲击发出的声音向别人表示有人在此: Can you go to the door? Someone's knocking. 你到门那儿去看看好吗? 有人敲门. * He knocked at the window to be let in. 他敲敲窗户要进来. Knock can denote an accidental action which hurts or breaks something *knock 可指意外的动作, 可造成伤痛或毁坏东西: I knocked my hand against the table. 我的手碰到桌子上了. * I knocked the plate off the table with my elbow. 我的胳膊肘把盘子从桌上碰掉了.
2 Bump means hitting something by accident and with a dull sound *bump 的意思是偶然地碰撞某物并发出低沉的声音: The bus bumped into the back of the car. 公共汽车砰的一声撞上了一辆汽车的後部. * He ran round the corner and bumped into an old lady. 他跑过拐角处, 撞着了一个老太太. * I bumped my head on the low beam. 我的头撞到低梁上了.
3 Bang suggests a harder blow and a louder sound. *bang 指撞击更重, 声音也更大. Banging may be intentional hitting, expressing anger or urgency 这种撞击可以是有意的, 表示气愤或着急: He banged his fist on the table to emphasize his argument. 他用拳头敲着桌子为自己的辩驳助威. * He banged on the door until it was opened. 他砰砰地敲门, 直到把门敲开为止. Banging may also be accidental and painful 这种撞击也可以是意外的及产生痛苦的: I banged my elbow on the corner of the table. 我的胳膊肘撞着桌子角了.
4 Bash is informal and means breaking or injuring something or somebody by hitting hard *bash 是口语用词, 意为猛力地撞毁某物或撞伤某人: The thieves bashed the woman over the head. 强盗猛击那女子的头部. * The car bashed into the tree. 汽车猛力撞着一棵树.