Present and past of verbs
The present ofthe polite form of verbs is formed by adding ‘masu’ to the indefinite base of the verb.
For ex.:
tabe (to eat) + masu=tabemasu
To make the past tense, change the final part of the verb from masu to mashita, from desu to deshita:
Examples:
Watashi wa ringo o tabemasu – I eat apples
Watashi wa ringo o tabemashita – I have eaten/ate apples
Inu ga imasu – There is a dog
Inu ga imashita – There was a dog
Jisho ga arimasu – There is / I have a dictionary
Jisho ga arimashita – There was / I had a dictionary
Kyō wa ame desu – It is raining today
Kinō wa ame deshita – It rained yesterday
Watashi wa tegami o kakimasu – I write a letter
Watashi wa tegami o kakimashita – I wrote a letter
Watashi wa tokei o mimasu – I look at the watch
Watashi wa tokei o mimashita – I looked at the watch
Karera wa jitensha de gakkō he kimasu – They come to school by bicycle
Karera wa jitensha de gakkō he kimashita – They came to school by bicycle
To make the sentence negative, use the indefinite base+masen (polite form) for the present, and indefinite base+ masendeshita (polite form) for the past.
Examples:
Watashi wa ringo o tabemasen – I don’t eat an apple / apples
Watashi wa ringo o tabemasendeshita – I didn’t eat an apple
Inu ga imasen – There is no dog
Inu ga imasendeshita – There was no dog
Jisho ga arimasen – There isn’t a dicionary
Jisho ga arimasendeshita – There wasn’t a dictionary
Colloquial form
The present tense of the colloquial form in the present tense is the same as the positive base:
taberu (to eat), iru (there is / are), aru (there is / are), desu (to be), miru (to see / to look).
Watashi wa ringo o taberu – I eat an apple
To make the past tense of the colloquial form of the ‘ichidan’ verbs, just add ta to the base of the verb:
Taberu present
Tabeta past
Iru present
Ita past
Aru present
Atta past
Da present
Datta past
Miru present
Mita past
For the ‘godan’ verbs the base changes in different ways before adding ta:
Kau (to buy) present
Katta past
Hanasu (to speak) present
Hanashita past
Tobu (to fly) present
Tonda past
Yomu (to read) present
Yonda past
Oyogu (to swim) present
Oyoida past
Tsukuru (to build) present
Tsukutta past
Kaku (to write) present
Kaita past
Finally, for the negative colloquial form, we use the negative base +nai in the present tense, and negative base+nakatta in the past:
Watashi wa ringo o tabenai – I don’t eat apples
Watashi wa ringo o tabenakatta – I didn’t eat apples
Inu ga inai – There is no dog
Inu ga inakatta – There was no dog
Jisho ga nai – There is no dictionary
Jisho ga nakatta – There was no dictionary