分析下这个句子.he had heard some of them from his father ,who had w

分析下这个句子.he had heard some of them from his father ,who had worked hard at his trade,but liked to read beter than to make shoes.
本人英语基础很差有点问题想问一下,who had worked hard at his trade这个从句中,had worked是否是过去完成时.这里为什么要特地用完成时?没搞懂.
另外还有一个句子.
One cold day the boy had stood looking at the white pattebs formed on the window by the forst.
这里面looking at the white pattebs 里的looking at为什么可以用现在进行时.从句或者补充句不是应该和主句时态一致吗?茫然,looking开始的后面的句子到底属于什么句子我也没搞明白.