重点讲解：
1. a fleet of
（尤指同一机构或统一行动的）车队；
eg. The company owns a fleet of car for its sale force to use.
这家公司拥有一个车队，供从事推销的雇员使用。
eg. A fleet of ambulances took the injured to hospital.
一队救护车把伤者送往医院。
2. two-way
双行的；双向的；
eg. Use two-way conversation to find and recruit top talent from within.
运用双向对话从公司内部发掘提拔优秀人才。
eg. This reflects a two-way causality.
这反映出一种双向因果关系。
3. a pair of
双；对；副；
eg. 72,000 pairs of hands clapped in unison to the song.
72，000双手和着歌曲整齐划一地打着拍子。
eg. On the mantelpiece are a pair of bronze Ming vases.
壁炉台上是一对明代的青铜花瓶。
