opportune
/ˈɒpətjuːn/adjective
1- (of a time) at which a particular action or event occurs, especially conveniently or appropriately（时机）恰好的; 适宜的：
he couldn't have arrived at a less opportune moment.
他当时来得太不是时候了。
1.1
- done or occurring at a favourable or useful time; well-timed适时的; 及时的：
the opportune use of humour to lower tension.
适时运用幽默来缓和紧张气氛。
派生词
opportunely
adverbopportuneness
noun词源
late Middle English: from Old French opportun(e)， from Latin opportunus, from ob- 'in the direction of' + portus 'harbour', originally describing the wind driving towards the harbour, hence 'seasonable'.