481. once and for all =once and forever永遠地 all at once (=suddenly, now) 立即,馬上 once in a while (=occasionally) 偶爾 (just) for once 就這一次

　　482. (all) by oneself 獨自(沒有別人幫助)

　　483. operate on sb. 給某人做手術 operation n. come go into operation開始運轉 putbring sth. into operation 使…投產,運轉

　　484. be of the opinion 持有…的看法

　　485. in one’s opinion 按某人的看法

　　486. be opposed to… 反對…

　　487. be opposite to 與…相反的

　　488. (be) in order(=acceptable)合適的,恰當的 in order 井井有條,處于良好狀態; out of order(=in bad condition)出毛病,發生故障

　　489. made to order 定做的(衣服)

　　490. originate infrom(=begin)起源于,由..引起

　　491. on the outskirts (of) 在城郊

　　492. owe…to 把…歸于…

　　493. on one’s own (=along, without help)單獨

　　494. of one’s own某人自己的

　　495. keep pace with 跟…齊步前進

　　496. go to great pains=take pains 下功夫,努力

　　497. part with (=give up, sell) 舍棄,賣掉

　　498. participate in (=take part in)參加

　　499. (be) particular about 講究,挑剔(吃,穿)

　　500. in particular (=especially) 特別是,尤其