that do,that doing,that done记得that是代词时,所代指的东西=that）,它与后面的do的关系（主动,被动）决定了动词的形式（doing or done）那 that do .sculptures that belong to part of our nation's cultural heritage.they a

that do,that doing,that done
记得that是代词时,所代指的东西=that）,它与后面的do的关系（主动,被动）决定了动词的形式（doing or done）那 that do
.sculptures that belong to part of our nation's cultural heritage
.they also need to understand what changes could be made to air pollution sources that cause the prolem（这句话不会翻译.）
好像还有that be .额 ,
他们也需要了解对于空气污染有什么样的变化that cause the problem。
全句是
to solve the acid rain problem,people need to understand how acid rain cause damage to the environment .they also need to understand what changes could be made to air pollution sources that cause the problem.

翻译好解决点就先说下翻译了：
they also need to understand what changes could be made to air pollution sources that cause the problem.他们同时得知道怎样的改变可能会变成造成这个问题的空气污染源
主句是 they also need to understand 后面是整个宾语从句,做understand 的宾语,说明知道的内容.可以单独拿出来看.
what changes could be made to air pollution sources that cause the problem.
what changes 做主语,怎样的改变.
that cause the problem 拿出来修饰 sources
主干是：sth could be made to sth 这样就比较明朗了
至于楼主说的that 后面接什么的问题,完全要看具体情况的.看that 是什么成分,如果是做主语,指代“那个”的话,后面是只有 动词的第三人称单数 和 is 的
比如：that is my father
或者 that matters a lot for me 那对我来说很重要
如果 that 是做关系代词的话就更重情况了
I don't think that doing exercise is useful 我不认为做运动有用 （doing）
it is a table that made of wood 这是一张木头做的桌子 （done）
I don't believe that is necessary 我可不认为那有必要 （is）

翻译：他们需要了解对导致这些问题的空气污染源还需要做什么改变