Pairs of Words

This is not a question so much as a compliment. I like the way the writers include potentially confusing pairs of words in the same lesson. In "Excuses for Being Late" I find these:

    九 jiu3 (nine) and 久 jiu3 (long time/long duration) and 就 jiu4 (at once/then/right away/only/(emphasis)/to approach/to move towards/to undertake)
    关系 guan1xi4 (relations) and 关心 guan1xin1 (caring/concerned)
    其 qi2 (his/hers/its/their/that/such/it (refers to something preceding it)) and 起 qi3 (to rise/to raise/to get up/starting)
    事 shi4 (matter/thing/item/work/affair) and 释 shi4 (explain/to release)
    口 kou3 (mouth) [in 借口 jie4kou3 (excuse/pretext)] and 扣 kou4 (10 percent/button/detain/dock or deduct)

Then, if we also consider the expansion sentences, we get more pairs:
    已经 yi3jing1 (already) and 一定 yi1ding4 (definitely/surely/certainly/necessarily/fixed/a certain (extent, etc.)/given/particular)
    不管 bu4guan3 (no matter (what, how)/regardless of/no matter) de 管 guan3 (to take care of/to control/to manage/to be in charge of/to look after/to run/tube/pipe) and the above 关 guan1
    是 shi4 (is/are/am/yes/to be) and the above 事 shi4 and释 shi4
    完 wan2 (to finish/to be over/whole/complete/entire) in完不成 wan2bu4cheng2 (to be unable to complete) and晚 wan3 (evening/night/late)

Well done Team.

-Tom