以下两句均出自《动物庄园》

1，The bits, the nose-rings, the dog-chains, the cruel knives with which Mr. jones had been used to castrate the pigs and lambs, were all flung down the well.

因为castrate是动词原型，所以按be use to习惯于来解不对，按use to曾经来解，那么前面的had been是怎么回事？

2.It was noticed that they wagged their tails to him in the same way as the other dogs had been used to do to Mr. Jones.

和上句一样had been无法理解。

其次，本句的had been如果按被动语态来理解，按前面as比较的对象应该是tails才对吧，那么dogs是不是该变成dogs'？