some cakes与piece of cake

some cakes与piece of cake some cake还是some cakes pieces of cake?and pieces of cakes 有什么不同?and basket可以用piece a piece of cake cake的用法以及是two pieces of cakes还是two pieces of cake,some cake还 Just a piece of cake! it's time for some cake为什么cake而不是cakes two bags of ( ) A.cake B.cakes It's a piece of cake a piece of cake啥意思 a piece of cake=easy吗? This is not my piece of cake.