划出下列复句的关联词并说出从句种类.
1.We must study hard as Comrade Li did.( )
2.I didn't tell him when he worked in the factory.( )
3.I don't know which one is the best.( )
4.Do you know the student who will take part in the maths contest?( )
5.She asked whose handwriting was the best in your class.( )
6.Could you tell me if you will come.( )
7.He came up as we were talking about him.( )
8.Though the man is very old .he still works very hard.( )
9.Great changes have taken place since China was liberated.
10.That boy is so young that he can't go to school( )