A practical english grammar - Vyssaja skola 1978
Past tense
Sound symbols
Regular verbs. Most verbs in English form their past tense by the addition of an ending that is spelled -ed (or just -d if the base is spelled with final -e). This spelling represents three different sounds, depending on the final sound in the base word.
If the base ends in /t/ or /d/, the ending is /d/ (an extra syllable).
love loved /d/
bow bowed /d/
call called /d/
If the base ends in a voiced consonant (other than /d/) or a vowel, the ending is /d/.
like liked /t/
miss missed /t/
watch watched /t/
wish wished /t/
If the base ends in a voiceless consonant (other than /t/) the ending is /t/.
These base verbs are all called regular, because they are the most numerous, and their past tense forms can be made according to a rule.
A spelling rule. The final consonant letter of a base word is doubled before -ed (and other suffixes beginning with vowels, such as -ing and -er) if all of the following conditions are met: 1) if the base ends in a single consonant letter; 2) if the final consonant is preceded by a single vowel letter; and 3) if the word has only one syllable, or if the main stress of the word is on the last syllable.
Study these examples:
rob robbed but roam roamed
trim trimmed contain contained
can canned resist resisted
rot rotted
control controlled
In words like travel and focus, with the main sttess on the first syllable, American usage prefers the single consonant (traveled, focused) while British usage prefers the double (travelled, focussed).
Irregular verbs. There are in English about 250 verbs (fewer than that in common use) whose past tense is irregular. By this we mean that the past tense cannot be formed according to a rule but must be learned. Here are some examples:
begin began buy bought
break broke tell told
There is a complete list of these verbs on page 219. The student should study it and make sure he knows all of those verbs, together with their correct pronunciation.
Sentences with the past tense. The past tense of ordinary verbs (that is, those other than be), is used only in affirmative statements. The same form is used with all subjects.
They called me last night.
My father bought a new coat.
I saw Henry at school yesterday.
Negative and interrogative constructions are made with did, the past tense of do. The base form of the verb is used with did.
I didn’t study English last year.
They didn’t call yesterday.
I didn’t see Henry at school yesterday.
Did they study English last year?
Didn’t they call yesterday?
Didn’t you see Henry yesterday?
Meaning of the past tense. The past tense relates events or describes conditions in the past. These may be single occurrences or they may be habitual or repeated occurrences.
I walked to school every day when I was a child.
I walked to school yesterday.
A very important use of the past tense in English is to express unreal events or situations. For discussions of this meaning, see Chapters 12 and 18.