We much admire his working so hard.his working 后面为什么不加is?

We admire his working so hard.我们钦佩他工作努力.这里so hard在句子作什么成分. He was so hard working that in his life time请问这句话为什么加that? He is working hard-----his lessons This boy is working hard on his studis(改为一般现在时) one of his good 什么（quality）is working hard One of his good_________(quality) is working hard. 翻译This boy is working hard on his studies. She is a hard-working student that we cannot admire her pers 为什么 Now i am working much hard than before?这儿为什么用hard ,后面有th Larry is much less hard-working,though. working so hard now working so hard