1.oil barrel 油桶

例句:To keep warm they burnt wood in a rusty oil barrel.
他们在一只生锈的油桶里烧木柴来保暖。

2.mobile technology 移动技术

例句:Contemporary IT is increasingly a function of mobile technology, pervasive or ubiquitous computing, and of course, cloud computing.
当代的IT不断向移动技术、普遍存在的计算和云计算发展。

3.in exchange for 交换

例句:The trade unions bargained away their rights in exchange for a small pay rise.
工会不惜牺牲自己的权利以换取微薄的加薪。

4.a trace of 一丝

例句:His face was unmoved, but on his lips there was a trace of displeasure.
他脸上没有丝毫表情，但嘴角流露出一丝不悦。