I was watching TV... my mother came home.
1-if, 2-and, 3-when , 4-but​

I was watching TV when my mother came home.

1 действие прерывается другим это Past Continuous

Здесь будет when

Данное слово подходит как и по смыслу, так и по грамматике.

When - (когда)

Перевод предложения: Я смотрел телевизор, когда моя мама пришла домой

ответ:

father-it's time to go to bed.

son phantom-okay, but look under the bed. suddenly there's a monster

father-well

son - there, on the bed someone lies, i hid under the bed.

daughter phantom-what's wrong dad?

father-nothing

daughter – dad, what's wrong with you?

wife-what happened dear?

father-call the police and the priest

son and daughter-what's going on here? mom? ! dad? !

part 2

detective - what's going on?

priest – got together to say a prayer

father-well

part 3

detective - can you tell me what happened?

wife-i remember only the moment, when in the door someone began to break

detective-okay, thank you rest, if you remember anything, call me

part 4

detective - who's there?

the son of the phantom-this the second i was too kind, and i killed him

detective-where's your sister?

part 5

the daughter of the phantom how dare you kill my brother? gangplank, like my brother a painful death! au revoir!

the detective-the devil had missed her!