题目：
A memory--memory, machine instruction for a certain machine has the following format. (Such an instruction is similar to a register—register instruction except that the operands are displaced addresses in memory.)
Which of the following could be an assembly language instruction that would be translated into a memory—to—memory instruction for this machine( ).
A) ADD 10(R1) ,20(R2) B) ADD(10R1), (20R2)
C) ADD R1,10(R2),20 D) ADD R1,10,20(R2)
答案：
参考答案：A
