病気の間に彼はひどくやせた。
tbd
While he was sick, he lost a lot of weight.
During his illness, he fell away horribly.
While he was sick, he became very thin.
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痩せる， 瘠せる， やせる
1. to become thin, to lose weight, to slim
2. to become impoverished (of soil), to become sterile, to become infertile, to become barren
变瘦，减肥，瘦身；贫瘠化，失去肥力，变得不孕不育，变得荒芜
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