When my sister (enter) the room, I (watch) TV. a)entered, watched b) was entering, were watching c)entered, was watching They (sit) in a state of tense attention while Tom (try) to concentrate.a)sat, tried b)were sitting, were trying c) sat, was tryingWhen I (receive) the first postcard, I (think) it was a joke. a) was receiving, thought b) received, thought c) received, was thinking Mike (return) to sofa and (pick up) the magazine which he had left.returned, picked up was returning, picked up returned, was picking upMary (look) at her several times during the morning.was looking b) looked c) was lookWhen in Spain we (go) to the beach twice a day a)was going b) went c) were goingLast week I was on a diet, I (not eat) any sweets at all.a)wasn’t eat b) wasn’t eating c) didn’t eat The boys (play) tennis when their mother (call) themplayed was calling b)were playing was calling c) were playing called ​