Teach Us, Teacher
Three groups of verbs (Lesson 40)Japanese verbs are divided into three groups. Each group has its own patterns of conjugations. "Group 1" are the verbs that have the vowel I in the syllables before MASU. KAKIMASU (to write) is an example. When the verbs in this group conjugate, the syllables before MASU change.
Let’s make the dictionary form of KAKIMASU (to write). Here, you change KI, the syllable before MASU, to KU, and say KAKU. To get its TA-form, that is, the past or the perfective form, you change KI to I, and say KAITA (wrote, have/has written). You learned the patterns of these conjugations of syllables before MASU with songs in Lesson 12. Please review that.
"Group 2" is the verbs that have the vowel E in the syllables before MASU.
TABEMASU (to eat) is an example. To turn it into the dictionary form, you replace MASU with RU, and say TABERU. To turn it into the TA-form, you replace MASU with TA, and say TABETA (ate, have/has eaten). In "Group 2," there are some verbs that have the vowel I in the syllables before MASU, such as MIMASU (to watch, to see, to look at). But these are only a few.
"Group 3" has two verbs, SHIMASU (to do), and KIMASU (to come). They conjugate irregularly. But they are just two. So, please memorize their conjugations.
The dictionary form of SHIMASU (to do) is SURU, and its TA-form is SHITA (did). The dictionary form of KIMASU (to come) is KURU. Its TA-form is KITA (came).
We have also made available the tables of conjugation patterns of verbs to the TE-form and the NAI-form in the Learning Tools pages for the past lessons. So, please refer to them.