曾
zēng · HSK 4
once
Sound-alike: zēng rhymes with English 'sung' — 'I have sung that song before.'
曾 marks past experience: 'once did, ever did.' Hook the tone (zēng, level 1) to 'sung' and the meaning to a completed past action you've done before.
曾 — top 八 + 田-like body + 日 (steamer pictograph)
曾 originally pictured a tiered bamboo steamer with rising vapor, the ancestor of 甑 'steamer pot.' It was borrowed phonetically for the grammatical meanings 'once, formerly' (zēng) and 'great-grand-' in kinship terms. Later 甑 was created with the 瓦 'tile/pottery' radical to keep the original cooking-vessel sense.