Was/were, There was/there were: Como utilizar

Hello! Gente, estava fazendo um exercicio sobre to be e there to be no passado e fiquei com algumas dúvidas:
"The sky was blue and ____________ not any clouds in the sky." there was/were
"Who _________ at your house yesterday?" was/were
"______________some music" there was/were
"_____________ much soda" there wasn't/weren't
"_____________a lot of plates" there was/were


Alguém poderia me explicar como esses casos funcionam? Thanks!