1.back prep. 在…后面行，背部，后部 adv．回来支持
back out 退出
a:wasn't bert supposed to sing tonight?
b:yes, but he backed out at the last minute.
in the back 在后面
a:i'm looking for a lightweight jacket...navy blue...medium...
b:let's see. have you checked the sales rack in the back? there were still a few there yesterday.
on one's way back from work 下班回来的路上
例句：he'd better stop at the grocery store on the way back from work.
polish the furniture 给家具打蜡
例句：he vacuumed the rug and polished the furiture．
3.opening n. 开张，通道 adj．开始的，开场的
job opening (offer)工作机会(job opportunity; vacancy)
1.how did the woman learn about the job opening?
2.job offers are up 16 percent from iast year．