concentrate

vt.

1. 集中；聚集，集結[O][（+on/upon）]
   We must concentrate our attention on efficiency.

   我們必須把注意力集中在效率上。

   Our population is concentrated in the big cities.

   我國人口集中在大城市裡。

2. 濃縮

vi.

1. 集中；聚集，集結[Q]
2. 全神貫注；全力以赴[（+on/upon）]
   She couldn't concentrate on a book very long.

   她不能長時間專心讀一本書。