the past progressive tense

study the following sentences ?
1 i was playing the guitar at eight o , clock last night
   i wans t playing the guitar at eight o clock last night
   was I playing the guitar at eight o clock last night ?
yes , you were . / yes , you were playing the guitar at eight o clock last
night .
no , you weren t / no , you  weren t playing the guitar at eight o clock
last night .

2 at  eight o clock last night , the was playing the piano
   she wasn t playing the piano at eight o clock last night
   was she playing the piano at eight o clock last night ?
    wasn t the playing the piano at eight o clock last night ?
   yes , she was
    no , she wasn t