Form

Form

Simple Past	Past Progressive
irregular verbs: see 2nd column of irregular verbs I spoke regular verbs: verb + ed I worked	past form of 'be' + ing form of verb   I was speaking you were speaking he / she / it was speaking we were speaking they were speaking
Exceptions
Exceptions when adding 'ed' : when the final letter is e, only add d.Example: love - loved after a short, stressed vowel, the final consonant is doubledExample: admit - admitted final l is always doubled in British English (not in American English)Example: travel - travelled after a consonant, final y becomes i. (but: not after a vowel)Example: worry - he worried but: play - he played	Exceptions when adding 'ing' : silent e is dropped (but: does not apply for -ee)Example: come - coming but: agree - agreeing after a short, stressed vowel, the final consonant is doubledExample: sit - sitting final l is always doubled in British English (not in American English)Example: travel - travelling final ie becomes y.Example: lie - lying

Past Continuous and Past Simple

1.  The most common use of the past continuous tense is to talk about something that was happening around a particular time in the past.

• What were you doing at 8 o’clock last night? I was watching television.

I started watching television before 8 o’clock and I continued watching it after 8 o’clock.

• In 1994 he was working in a small town in Poland.
• At 6 o’clock on Saturday morning we were travelling to the airport.

2. We often use the past continuous and the past simple tense together. When this happens, the past continuous describes a longer, ‘background’ action or situation and the past simple describes the action or events.

• When I woke up this morning it was raining and my father was singing in the kitchen.
• I was walking home, whistling happily, when I saw two masked men run out of the bank.

Often, the ‘action’ described by the past simple tense interrupts the ‘situation’ described by the past continuous tense.

• I broke my leg when I was skiing.
• I was playing a computer game when the doorbell rang.

Notice that the past continuous describes ‘situations’ that go on for some time – ‘skiing’ and ‘playing’ but the past simple describes ‘actions’ that happen quickly – ‘broke’ and ‘rang’.

Notice too the important difference between these two sentences.

• When they arrived, Jeff was cooking dinner. Jeff started cooking before they arrived.
• When they arrived, Jeff cooked dinner. Jeff started cooking dinner after they arrived.

Answer

The short answer to your question is that the verb that follows did should be used in its base form. Read below for more information.

The verb did, the past tense form of do, commonly appears before another verb in these two sentence types:

1. Questions about the past

• What did you eat? (The two verbs are did and eat.)
• Did you eat pizza? (did, eat)

2. Negative statements about the past

• I didn't stay late.(didn't, stay)
• Julia didn't come at all last night. (didn't, come)

In both of these sentence types, did is an auxiliary verb (or “helping verb”) that is followed by a main verb, which carries the real verb meaning.

The auxiliary verb (did) is marked for past tense, but the main verb is not. It appears in its base form. A helpful way to remember this is that when there is an auxiliary verb, the main verb does not need to be marked for tense, because the tense is shown in the auxiliary. However, in a sentence about the past without an auxiliary verb, the main verb does need to be in the past tense form, as in this sentence:

• He ate a whole pizza. (ate, the only verb, is in the past tense form)