About
HSK levels

    1. reason; cause
    2. intentional
    3. former; old
    4. therefore; hence
    5. happening; instance
    6. friend
    7. (of people) to die, dead

    他迟到的原故是因为堵车了。 Tā chídào de yuángù shì yīnwèi dǔchē le.