In some countries, the government has tried to reduce traffic. For instance, they imposed a congestion tax during rush hour. Do you think this development is positive or negative?

这里 this development指的是the government has tried to reduce traffic还是they imposed a congestion tax during rush hour？
因为这个涉及到后面我找关键词从哪句话里面找，所以很重要。

我自己的想法：
应该是 the government has tried to reduce traffic. 因为这个说的是一般情况，而后面for instance说的是其中一种reduce traffic的措施，是特殊情况。所以应该从 the government has tried to reduce traffic这句话找关键词，推导的时候稍微提到for instance那句话就可以了

但是，又觉得the government has tried to reduce traffic.这句话里面，着实也找不到啥可以作为关键词的，traffic和government好像都不太像是关键词（直觉），而for instance这句话里面的congestion tax、rush hour更像是关键词。

所以，
1、推导的时候，关键词从哪句话里面找？
2、当从其中一句话找关键词时，另一句话在推导过程中是不是稍微提到就可以了？