only so much困难

But mayors and councillors can only do so much about a problem that is far bigger than any one city or town.

但对于一个远远超出任何一个城镇范围的问题，市长和议员们所能做的十分有限。

Part of the issue is that airports have only so much room for screening lanes.

问题的部分原因在于机场能用于安检通道的空间有限。