-----------------------------------
下がる， 下る， さがる
1. to come down, to go down, to fall, to drop, to sink, to get lower
2. to hang, to dangle
3. to move back, to step back, to withdraw, to retire
4. to deteriorate, to fall off, to be downgraded
5. to get closer to the present day
6. below, south of
挂，垂下；下降，下行，坠落，下坠，下沉，降低；回调
は
1. indicates sentence topic
2. indicates contrast with another option (stated or unstated)
3. adds emphasis
指示句子的主题；表示与另一选项（无论是否明确提及）形成对比；表示强调
に
1. at (place, time), in, on, during
2. to (direction, state), toward, into
3. for (purpose)
4. because of (reason), for, with
5. by, from
6. as (i.e. in the role of)
7. per, in, for, a (e.g. "once a month")
8. and, in addition to
9. if, although
tbd
