Trams are double-decker ones b___ there are more people on Green Island

问题描述:

Trams are double-decker ones b___ there are more people on Green Island

but 只不过,但是
这句话的意思是:
有轨电车是双层的,不过在绿岛上有更多的人.
(也就是说,即使是双层的有轨电车也装不下绿岛上的那么多人.)