PAST TENSE AND PAST CONTINUOUS TENSE

Past simple tense

There are two types of English verbs in the past simple - regular and irregular verbs. They have different forms for positive statements (regular verbs: I play - I played, irregular verbs: I go - I went), but questions and negatives are made in the same way.

Positive statement: I worked, He worked, I draw - He drew
Negative statement: I did not work (I didn't work), He did not work (He didn't work), I did not draw (I didn't draw), He did not draw (He didn't draw)
Question form: Did you work? Did you draw?
Negative question: Did you not work? (Didn't you work?) Did you not draw? (Didn't you draw)
See also how to make the past simple in the passive voice.

Regular verbs usually end in -ed. This ending is the same for all persons, singular and plural.

The auxiliary verb did is not used with "to be" (Were you a student? He was not happy.), in a specific type of wh- questions and modal verbs.

We do not use the auxiliary did to make indirect questions and reported questions either.

The negative question normally expresses a surprise.
Didn't you know it?

Use

1. We use this form for activities or situations that were completed at a definite time.

a) The time can be given in the sentence:
I came home at 6 o'clock. When he was a child, he didn't live in a house.

b) The time is asked about:
When did they get married?

c) The time is not given in the sentence, but it is clear from a context that the action or situation was finished.
He is 20 years old. He was born in Canada. 
Alan: I've been to Iceland. - Greg: Did you enjoy it?

2. We use it for repeated activities.
We walked to school every day. - And did you ever go by bus?

3. The past simple tense is used in stories to describe events that follow each other.
Charles entered the hall and looked around. He took off his coat and put it on a chair. He was at home.

Past continuous tense

Form

Positive statement: I was sleeping, You were sleeping
Negative statement: I was not sleeping (I wasn't .... ), You were not sleeping (You weren't .... )
Question: Were you sleeping? Was he sleeping?
Neg. question: Were you not sleeping? (Weren't you .... ?) Was he not working? (Wasn't he .... ?)
The past continuous tense is formed with the past tense of the verb to be and the present participle (-ing form).
See also how to make the past continuous in the passive voice.

Use

We use this tense for activities or situations that were not completed.
From 10 to 12 I was washing my car. I was in the garage. (I did not finish my work. It was in progress. I started before 10 and finished after 12.)
The sun was setting. The beach was changing its colours. (The sun was still in the sky when I was watching it.)
Compare this sentence with completed actions:
From 10 to 12 I washed my car. (I finished my work. (I started at 10 and finished at 12.)
Finally, the sun set. It was dark and we did not see the beach anymore. (The sun completely disappeared.)
We use the past continuous tense for uninterrupted activities or situations. If the action is interrupted (it is not continuous - something is done in more intervals or we did more things one after another), we use the simple.
Tom was watching TV on Sunday. x Tom watched TV in the morning and in the evening.
Yesterday I was working in the garden. x Yesterday I worked in the garden and on my house.

This tense is typically used:

1. To express the idea that an action in the past continuous started before the action expressed by the past simple tense and continued after it.
When she saw me, I was looking at the trees. (These two actions happened at the same time. I was looking at the trees for some time and she saw me in the middle of it.)
Compare:
When she saw me, I looked at the trees. (These two actions happened one after another. First she saw me and then I looked at the trees.)

2. With a point in time to describe an action that started before that time and continued after it.
At 8 o'clock Jane was doing her homework. (At 8 o'clock she was in the middle of the activity. She did not finish it.)
Compare:
At 8 o'clock Jane did her homework. (She started the activity at 8 o'clock and finished it.)

3. It is used to describe a situation, while the simple is used to express actions in stories.
The sun was shining. Jack and Jill were lying on the beach. Jack was reading a book and Jill was sleeping. All of a sudden, Jack raised his head. Jill woke up. Something happened.

4. It describes an activity which was not finished in contrast with the simple past, which describes a completed activity.
I was reading a book yesterday. And today I am going to continue.
I read the book yesterday. I can lend it to you now.

5. It can be used to show a more casual action, the simple is for a deliberate action:
I was talking to my neighbour yesterday. We had a nice chat. (I did not do it on purpose. We just met in the street.)
I talked to my neighbour yesterday. And he promised to help me. (I did it on purpose. I needed to ask him for help.)