A) The teacher wasn't talking (not talk) when Mary arrived. b) The pupils were playing (play) when the bell rang. c) Lucy was doing (do) her homework when someone knocked the door. d) Mark´s parents were writing (write) him a letter when they heard a crash. e) Ann wasn't sleeping (not sleep) when the alarm clock rang. f) They weren't watching (not watch) TV when their parents arrived.
b) The pupils were playing (play) when the bell rang.
c) Lucy was doing (do) her homework when someone knocked the door.
d) Mark´s parents were writing (write) him a letter when they heard a crash.
e) Ann wasn't sleeping (not sleep) when the alarm clock rang.
f) They weren't watching (not watch) TV when their parents arrived.