At this time last year, they ____________(build) this house.
A.built   
B.was built       
C.was building
D.were building

My mother ____________ (not do) the housework when my father came home.
A.didn’t do
B.didn’t doing
C.wasn’t doing
D.weren’t doing

My sister ____________ (read) books while my brother ____________ (play) football yesterday afternoon.
A.was reading - playing         
B.was reading- was playing
C.was reading – played          
D.read – was playing

My mother ____________ (cooking) lunch while my father ____________ (clean) the floor at 10 am yesterday.
A.was cooking – was cleaning
B.cooking – cleaning
C.cooked – cleaned                
D.was cooking - cleaned

He ____________ (chat) with his friend when his mother came into the room.
A.chatting         
B.chatted
C.was chatting
D.was chatted

They ____________ (work) when we got there.
A.was working
B.were working
C.working
D.was worked

He ____________ (type) a letter when his boss went into the room.
A.was typing    
B.typing
C.typed
D.was typed

Anne ____________ (ride) her bike to school when Peter saw her yesterday.
A.rode
B.was roding
C.was riding     
D.riding

She ____________(paint) a picture while her mother was making a cake.
A.was painted
B. painted
C.painting         
D.was painting

Man can hardly understand why many animals live their whole life in the desert, as   _____ .
A.sources of flowing water are rare in a desert
B.water is an essential part of his existence
C.water composes the greater part of the tissues of living things 
D.very few large animals are found in the desert