Zhuīgēn zhège wèntí yào cóng shí nián qián shuō qǐ.
Tracing this issue back, it goes back ten years.
Tips
usage
Most commonly appears in the four-character set phrase 追根问底 (zhuīgēn-wèndǐ) or 追根究底 (zhuīgēn-jiūdǐ), "to chase the root and ask the bottom" — i.e., relentlessly investigate. Standalone 追根 is a shortened, somewhat literary form.
