5. What __________ you __________ (to do) now? — I __________ (to drink) tea. __________ you __________ (to drink) tea at that time yesterday? — No, I __________ (not to drink) tea at this time yesterday, I __________ (to eat) a banana.

5. What are you doing now? — I am drinking tea. Were you drinking tea at that time yesterday? — No, I was not drinking tea at this time yesterday, I was eating a banana.

В первом случае необходимо употребить Present Continuous в вопросительной форме, т.к. действие происходит сейчас. Далее - Present Continuous, т.к. действие происходит сейчас. Далее - Past Continuous в вопросительной форме, т.к. действие происходило в определенное время в прошлом. Далее - Past Continuous в отрицательной форме, т.к. действие не происходило в определенное время в прошлом, и Past Continuous, т.к. действие происходило в определенное время в прошлом.

Ответ: What are you doing now? — I am drinking tea. Were you drinking tea at that time yesterday? — No, I was not drinking tea at this time yesterday, I was eating a banana.