HSK 1
Tāmen zhìjīn háishì hǎo péngyǒu.
They're still good friends to this day.
HSK 3
Zhège wèntí zhìjīn méiyǒu jiějué.
This problem hasn't been solved to this day.
HSK 4
Kēxuéjiā zhìjīn wúfǎ jiěshì zhège xiànxiàng.
Scientists still cannot explain this phenomenon.
