TSUMUGU · TOCFL B2 (est.) · 詞
光是
ㄍㄨㄤ ㄕˋ · guāngshì
adverb — just, merely, only (singling one thing out, often before listing more)
關 · Related
只zhǐshìmerely, only — the plainer adverb for the same singling-out單單dāndānsolely, just — emphasizes the one item, like