Simple past

The simple past tense expresses a past action or event the time of which may or may not be indicated.
Sentences in this tense have the following structure:

Subject + past tense form of the verb

I wrote to him yesterday.
We visited them last week.
She spoke eloquently.
Susie walked slowly.
She got up early in the morning.

Negative sentences in the simple past tense have the following structure:

Subject + did not + present tense form of the verb

I did not write to him yesterday. (NOT I did not wrote to him yesterday.)
We did not visit them last week. (NOT We visited not them last week.)
She did not speak eloquently.
Susie did not walk slowly.
She did not get up early in the morning.

Notes:

The contracted form didn’t is common in informal speech and writing.

She didn’t speak eloquently.
She didn’t walk slowly.

Past continuous tense

The past continuous tense represents an action as going on or being done continuously at some time in the past. Sentences in this tense have the following structure:

Subject + was/were + -ing form of the verb

The children were playing in the garden.
She was writing a story.
He was listening to music.
I was reading a novel.

Negative sentences in the past continuous tense have the following structure:

Subject + was/were + not + -ing form of the verb

The children were not playing in the garden.
She was not writing a story.
He was not listening to music.
I was not reading a novel.

Notes:

The contracted forms wasn’t and weren’t are common in informal speech and writing.

The children weren’t playing in the garden.
She wasn’t writing a story.
I wasn’t reading a novel.

Past perfect tense

The past perfect tense represents an action completed at some point in the past before some other past action commenced.
Sentences in this tense have the following structure:

Subject + had + past participle form of the verb

She had finished cooking when the visitors arrived.
I had seen him before he left for Chicago.

Negative sentences in the past perfect tense have the following structure:

Subject + had + not + past participle form of the verb

She had not finished cooking when the visitors arrived.
I had not seen him before he left for Chicago.

Note that it is possible to write the contracted form hadn’t instead of had not.

She hadn’t finished cooking when the visitors arrived.

Past perfect continuous tense

Structure: Subject + had + been + -ing form of the verb

We had been waiting for you since long.

Negative sentences in the past perfect continuous tense have the following structure:

Subject + had + not + been + -ing form of the verb

We had not been waiting for you since long.