- knock
 - [nɔk]
 - vi. 敲;打;敲击
vt. 敲;打;敲击;批评
n. 敲;敲打;爆震声 
反义词
           - v. praise
 
参考例子
           - 1.The medicine is effective for knocking colds.
 - 这种药祛除感冒很有效。
 
- 2.Yet people still knock him.
 - 人们还是想击溃他。
 
- 3.Does the bad man knock over the trees with the black car?
 - 这个坏人用这辆黑色汽车把这些树撞倒了吗?
 
英文解释
           - n.
 - 1.the sound of knocking (as on a door or in an engine or bearing)
 - 2.negative criticism
 - 3.a vigorous blow
 - 4.a bad experience
 - 5.the act of hitting vigorously
 
- v.
 - 1.deliver a sharp blow or push :
 - 2.rap with the knuckles
 - 3.knock against with force or violence
 - 4.make light, repeated taps on a surface
 - 5.sound like a car engine that is firing too early
 - 6.find fault with; express criticism of; point out real or perceived flaws
 
网络释义
               - knock
 - 敲,敲打; 敲门; 敲缸; 敲击;
 
- Knock back
 - 反座; (摇把)反击,(活塞)逆行,(曲轴)反转; 回击; 使...大吃一惊;
 
- knock up
 - 码纸; 筋疲力尽; 匆匆安排 使精疲力尽 [英](板球赛中)很快得分 [美俚](指男人)与...通奸; 叫醒;
 
- knock intensity
 - 爆震强度; 头部震动强度;
 
- pericardial knock
 - 心包叩击音;