D. was doing
Feedback We use the Past Continuous Tense when we talk about two or more simultaneous actions in the past. 'While' means 'at the same time'.The conjunction ‘while’ (also formal ‘whilst’) means ‘during the time that’, or ‘at the same time as’. We can use ‘while’ to mean ‘during the time that’, to connect two events happening at the same time.When we use the Past Continuous with two actions in the same sentence (as in the test sentence), it expresses the idea that both actions were happening at the same time. The actions are parallel: Carol was eating a banana and Sandy was doing his home task.