The lesson from dams is that big is not always beautiful.It doesn’t help that building a big, powerful dam has become a symbol of achievement for nations and people striving to assert themselves.

紅色部分的是主從復(fù)合句對嗎？即that building a big, powerful dam has become a symbol of achievement for nations and people striving to assert themselves為主語，謂語是doesnt help

網(wǎng)友理解正確。

It （形式主語）doesn’t help （謂語）that building a big, powerful dam has become a symbol of achievement for nations and people striving to assert themselves. （主語從句，真的主語外置）

主語從句剖析：

building a big, powerful dam （主語）has become （系動詞）a symbol of achievement （表語）for nations and people （狀語）striving to assert themselves（定語）