回复：回复：机油哪里去了? “车有三谬，先说其一：合成机油。”

"我曾就机油使用寿命专门咨询过美孚，答复是所有的美孚机油（普通，半合成与全合成）不开罐的贮藏寿命是十年，开罐后为一年."

I believe they are talking about the oil not in use but just sits then for a year.

"全合成机油的优点是低温流动性和高温抗氧化性能"

This is why fully synthestic oil lasts longer since it resists heat-induced oxidation better.

"也就是说在可以选择 也可以不选择使用合成机油时，使用合成机油在换油间隔上没有区别。"

Don't understand the logic based on the above statements.