大家认为两个由and or but连接的分句,提取句子主干时要把and or but后面的部分也算进去吗

题目

大家认为两个由and or but连接的分句,提取句子主干时要把and or but后面的部分也算进去吗
如：Building materials have changed in order to increase architectural size and strength,but physical laws of structure have not changed.
它的句子主干应该是building materials have changed but physical laws have not changed.还是building materials have changed.

答案

but后面的也算进去,but 强调but后面的