How many local symbol tables are created when macro A is called and begins to execute? Explain your answer.

%macro A(value=);
%B
%mend A;
%macro B;
%put The value to write is: &value.;
%put _user_;
%mend B;
%A(value=Today is Monday)



I print out this code:
one is : The value to write is: Today is Monday
the other : A VALUE Today is Monday

In the case, can we say that there is two local table?  Why the user-defined variable "VALUE" became capital words? I never defined before.

Could you any Da Niu tell me how it works ?

Sorry can't type Chinese.