A) The exercises were very difficult, nobody (know) ____ what to do with them.
1)had known
2)had knew
3)known
4)knew

B)Everybody (leave) ____ the house by the time I came home.
1)leaved
2)left
3)had left
4)had leaved

A) The exercises were very difficult, nobody knew what to do with them. (4)B) Everybody had left the house by the time I came home. (3)