The Simple Past Tense VS The Past Continuous Tense

Students who learn English as a second or foreign language often have difficulties when they are working with Simple Past tense and Past Continuous tense. They often find it difficult to tell the difference in meaning between "He had breakfast at six" and "At six, he was having breakfast", or between "I talked to him several days ago" and "I was talking to him the other day", or between "She always watched TV" and "She was always watching TV". It is very likely that they confuse these two past tenses. As a matter of fact, incorrect use of simple past tense and past continuous tense may lead to misunderstanding.

The following list may help you understand how simple past tense and past continuous tense are different in meaning and usage.

SIMPLE PAST TENSE	PAST CONTINUOUS
Used with an adverbial of time, to indicate a past action which probably started at the specified time. Digunakan dengan keterangan waktu untuk menunjukkan kejadian yang berawal pada waktu tersebut. E.g.: He had breakfast at six. When she arrived, I called Lenny.	Used with an adverbial of time, to indicate a past action which started before, was happening, and probably continued after the specified time. Digunakan dengan keterangan waktu untuk menunjukkan kejadian yang sedang berlangsung pada saat itu (dimulai sebelumnya, dan mungkin berakhir sesudahnya). E.g.: At six, he was having breakfast. When she arrived, I was calling Lenny.
To indicate a more permanent past action. Untuk kejadian lampau yang bersifat agak permanen. E.g.: He lived in Malang for six years. The old tree stood in the yard for more than a hundred years.	To indicate a temporary past action. Untuk kejadian lampau yang bersifat lebih sementara. E.g. It happened while I was living in Malang ten years ago. I was sitting at my table when the teacher came in.
To indicate an unusual or deliberate past action instead of normal occurence. Subject had the initiative. Untuk kejadian lampau yang tidak biasa,  disengaja dan bukan hasil dari kejadian normal. Ada inisiatif dari Subyek untuk melakukannya. E.g.: I talked to him on that matter. He washed the car for about an hour.	To indicate an usual or unintentional past action, or one which resulted from a normal occurrence. It is not clear who took the initiative. Untuk kejadian lampau yang tidak disengaja, atau yang merupakan hasil dari kejadian normal/biasa. Tidak jelas siapa yang mengambil inisiatif. E.g.: I was talking to him the other day. She was walking home that evening.
To indicate a repeated past action which happened several times. Untuk kejadian lampau yang berulang-ulang atau terjadi beberapa kali. E.g.: I met him several times. She sent me a few letters.	To indicate parallel actions. Untuk lebih dari satu kejadian lampau yang sedang terjadi secara bersamaan. E.g.: Between one and two, I was doing the shopping and walking the dog.
Used with "always", to indicate a habitual past action. Dengan "always", menceritakan kebiasaan waktu lampau. E.g.: She always watched TV before going to bed.	Used with "always", to indicate a repeated and annoying past action. Dengan "always", menceritakan kejadian lampau yang berulang-ulang dan terasa mengganggu/menjengkelkan. E.g.: They were always playing the music loudly.
In narratives, to indicate events or actions. Dalam narasi, menggambarkan peristiwa atau kejadian. E.g.: Suddenly, the door opened and a man stood at the door.	In narratives, to indicate background events or descriptions. Dalam narasi, memberikan deskripsi atau latar belakang. E.g.: The bride was wearing a white dress and carrying a bouquet of lilies. The bridegroom was trembling and looking pale. Suddenly, ....

Note:
We can use the Past Continuous in "I was wondering, I was hoping, and I was thinking" to make a request or suggestion sound more polite.
Kita bisa menggunakan bentuk Past Continuous dalam "I was wondering, I was hoping, and I was thinking" untuk membuat suatu permintaan atau saran terdengar lebih sopan.
to do an exercise about the Simple Past and the Past Continuous tense.
Reference:

1. Thomson & Martinet. A Practical English Grammar (4th Ed). Oxford: Oxford University Press, 1986, p. 164-165.
2. Swan, M. Practical English Usage. Oxford: Oxford University Press, 1980, p. 468-470.