1- colourless = without colour
2- odourless = without smell
3- tasteless = without taste
4- melts = change from solid to liquid
5- boils = change from liquid to gas
6- essential = absolutely (100%) necessary
7- medicine = the treatment of injuries and illnesses by doctors and nurses
8- application = uses
9- combustion = burning
10- inhibits = prevents, or decrease the rate of
11- excluded = kept out of; not allowed to enter
12- rigid = not easy to bend; not flexible; stiff
13- inner = opposite of outer
14- assembly = a number of parts which have been put together to make up one object
15- display = show
16- adjust = change in order to correct or make more suitable
17- image = picture
18- brightness = the amount of light which a source (e.g. a lamp) gives out
19- component = part
20- implement = tool