A mixture is several pure substances combined.Unlike a compound,these substances can be physically separated and when they are combined,the amounts of each substance are not fixed.
One kind of mixture is a solution.A solution is a mixture of two or more substances in which one or more of these substances (solutes) is dissolved in another substance such as water or another sort of liquid (solvent).
简易的说mixture是多种物质的混合,如果一种物质溶于另一种物质则成为solution.Solution是mixture的一种特殊形式.
补充：solution里的物质很难被分离.(一般需要蒸馏,化学反应等手段才可以）