Объяснить чем они отличаются?

1) I was drinking tea two o'clock yesterday

2) I had drunk tea two o'clock yesterday

3) I drank tea two o'clock yesterday

Есть ошибки?

Ответ:

1) I was drinking tea two o'clock yesterday when she called .-Past Continuous

2) I had drunk tea by two o'clock yesterday

-Past Perfect

3) I drank tea two at o'clock yesterday  and then I went shopping.-Past Simple

Объяснение: