1. When the bus was arriving , we missed it because we were talking .
=> was arriving => arrived
2 . During the Christmas holiday,she was eating too much and watching TV too much 
=> Was eating => ate ; watching => watched 
Julian was learning all about computer games by the time he was six.
Julian had learnt all about computer games by the time he was six.

My grandfather was owning a hotel by the beach until he sold it last year.
My grandfather owned a hotel by the beach until he sold it last year.