1. （被車(chē)）撞倒 If someone is knocked down or is knocked over by a vehicle or its driver, they are hit by a car and fall to the ground, and are often injured or killed.
e.g. He died in hospital after being knocked down by a car... 他被車(chē)撞倒后死在了醫院。 e.g. A drunk driver knocked down and killed two girls... 一個(gè)酒后駕駛的司機撞死了兩個(gè)女孩兒。
2. 推倒，拆掉，拆毀（建筑物） To knock down a building or part of a building means to demolish it.
e.g. Why doesn't he just knock the wall down?... 他為何不干脆把墻推倒？ e.g. They have since knocked down the shack. 從那以后他們拆掉了簡(jiǎn)陋的棚屋。
3. 降（價(jià)）；殺（價(jià)）；減（量） To knock down a price or amount means to decrease it.
e.g. The market might abandon the stock, and knockdown its price... 市場(chǎng)可能會(huì )拋售該股票，從而令其股價(jià)下跌。 e.g. It manages to knock rents down to $1 per square foot. 成功地將租金降到每平方英尺1美元。
in AM, usually use 美國英語(yǔ)通常用 bring down
knock down英英釋義
verb
1. shatter as if by explosion
Synonym: blast
2. cause to come or go down
e.g. The policeman downed the heavily armed suspect The mugger knocked down the old lady after she refused to hand over her wallet