week#4

enzyme (n)
 a substance, produced by all living things, which help a chemical change happen or happen more quickly, without being changed itself

fermentation (n)
 a state of political or social excitement and counfusion

crack(v)
 to break, to hit, to make a sharp sound

subsidence (n)
 the process by which an area of land sinks to a lower level than normal, or by which a building sinks into the ground

tilt (v)
 to move, or ,make something move, into a position with one side or end higher than the other


Source: BBC Words in The News
          http://www.bbc.co.uk/worldservice/learningenglish/language/wordsinthenews/index.shtml