字根 tain,ten,tin 握住，維持

tenable

tenacious

tenancy

tenement

tenant n. 房客

abstain v.戒除 (放棄握住)

attain

contain

content

continue

continent

detain

distain

lieutenant n. 中尉

entertain

maintain

obtain

pertain v. 屬於 ，有關 (per 完全的)

pertinacious

retain

sustain