The first balls made specifically for basketball were brown

一定要记住：在每一个句子里，在无连词的情况下，谓语动词（包括被动语态、系表结构）必须有一个而且只能有一个。如果既用were made，又用were brown，又不是两个句子，又没有连词，当然是错误的。

分析一下原句：made specifically for basketball是过去分词做后置定语。The first balls were brown.是系表结构，这已经是一个完整的句子了。

如果这样写，就是正确的：The first balls which were made specifically for basketball were brown.因为这是两个句子，一个是定语从句：which were made specifically for basketball，一个是主句：The first balls were brown.所以就没问题。实际上，原句可以看成是这种情况省略了which were

或者这样写，也是正确的：The first balls were made specifically for basketball and they were brown.这也是两个句子，用连词and连起来了。

再或者这样写，也是正确的：The first balls were made specifically for basketball and were brown.这是一个句子，有两个谓语，但是用连词and连起来了，所以正确。但是一般不要这样写，一般都是用上面那三种。

其实是用了的，不过这里省略了

The first balls (which were) made specifically for basketball were brown

两种语法形式都对