Grouping of verbs

All the 1st group verbs, such as 「あいます」/「わかります」 have an [i] sound immediately before 「ます」(and there are two or more syllables before 「ます」), while most of the 2nd group verbs have an [e] sound immediately before 「ます」 like 「たべます」/「あつめます」. 

There are exceptional cases to the above rule: 1) Ci ます(C represents a consonant, so the vowel before 「ます」 is [i] but only one syllable) this type of verbs belong to 2nd group without exception. 

There are several 2nd type verbs unable to be distinguished only by 「ます」form, such as 「おきます」”to wake up”/「かります」”to borrow”. 

You need to memorize that these verbs belong to 2nd group, not 1st. Fortunately, the number of verbs is small, less than ten at the elementary level. All the examples up to D30 are 「あびます」, 「おきま す」, 「おります」, 「かります」, 「できます」.

There are only two irregular verbs, 「します」”to do”, 「きます」”to come”, in the Irregular Group (Group 3). There are also many compound verbs like 買い物します (kaimono shimas), 勉強します(benkyoshimas).

You can download here, a list of the verbs we studied until know divided into groups