6.a)The Peon rang the bell.-Simple past
b)The gardener was watering the plants.-Past continuous
c)The moon revolves around the Sun.-Simple present
7.a)Six of us went to the store with Sanya.(me/us/you)
b)Every Monday Mohan goes for swimming with them.(I/them/he)
c)She started moving after a few days.(she/her)
8.a)Jhon gave him a book.-He was given a book by Jhon./A book was given to him by Jhon.
b)She will write a letter.-A letter will be written by her.