Absolute references are the opposite of relative addressing. A dollar sign is placed before each letter and number in an absolute reference, for example, $A$1:$B$2.
与相对引用相反，绝对引用上述单元格区域的表达方式是：$A$1:$B$2。也就是说在每个单元格坐标说明之前需插入一个美元符号。