HSK 6
日后
rìhòu名
sometime; someday (in the future)
这些资料日后可能有用。
Zhè xiē zī liào rì hòu kě néng yǒu yòng.
These materials may be useful someday.
Say it
Hold the button, say it, then let go.
Other HSK words sharing a character
Also free:
New in the HSK 3.0 word list at level 6.