1.occupy oneself with (in) 忙于(某事)
2.it occurs to sb. that… 某人想到…
3.be made from 由~~原料制成
4.be made of 由~~材料制成
5.make into 把~~制成,使~~转变为
6.by occasion of (=because of) 由于
7.once and for all =once and forever永远地 all at once (=suddenly, now) 立即,马上 once in a while (=occasionally) 偶尔 (just) for once 就这一次