When a student calculated the volume of a beverage bottle, he sloppily wrote the unit "liter" into "milliliter", which resulted in a difference of 1998 ml from the correct answer. What is the actual volume of the beverage bottle in liters?
一位同学再计算饮料瓶的容积时，由于马虎把单位"升"写成了"毫升"，这样就与正确的答案相差了1998毫升，这个饮料瓶的实际容积是多少升．
<gadget id="calculator">1 / 1_000</gadget>
<output>1/1_000 = around 0.001</output>

<gadget id="calculator">1 - (1/1_000)</gadget>
<output>999/1_000 = around 0.999</output>

<gadget id="calculator">1_998 / (999/1_000) / 1_000</gadget>
<output>2</output>

<result>2</result>