From dictionary entry to polite sentence
You already know 食べます and 読みます. A dictionary often lists 食べる and 読む instead. These are the same verbs in a different form. This lesson connects dictionary entries to the sentences you already use. If needed, review the four polite endings in the verb bridge, the actions in lesson 30 and action locations in lesson 32.
Connecting the dictionary to your sentence
The dictionary form is the form used to look up a verb. 食べる means ‘to eat’; 食べます is the polite non-past form you already use. This change is not about the subject: 食べます can refer to ‘I eat’, ‘you eat’ or ‘she eats’ when context makes that clear. Here the change concerns politeness, not a different person.
There are three conjugation groups. In this lesson, use the group stated with each verb. Learn it as part of the word, just like its pronunciation. Looking only at a final る is insufficient: 食べる and 帰る both end in る but follow different rules. Keep the form, reading and group together.
We practise one direction: dictionary form → polite ます form. Dictionary forms also occur in ordinary Japanese sentences, but this lesson does not yet teach informal conversation. You do not need to guess an unfamiliar dictionary form from a ます form either.
食べる
食べます
Group 2: る makes way for ます
Start with group 2. Remove only the final る and add ます. 食べる leaves 食べ, giving 食べます. Everything before that final る stays in place; you do not change べ to another sound.
The same simple operation works for 見る and 起きる: 見ます and 起きます. Both belong to group 2 even though their ます forms contain an i sound. An i sound before ます therefore does not automatically mean group 1. Use the verb's group rather than an isolated sound trick.
食べます
見ます
起きます
Group 1: the final kana changes
For group 1, replace the final kana of the dictionary form with its corresponding i kana and add ます. 読む ends in む: む changes to み, giving 読みます. 飲む follows the same pattern: 飲みます. In 書く, く changes to き: 書きます. The verb's meaning stays the same.
This is a kana conversion, not an instruction to replace a letter u with i in romanisation. The full reference row is: う→い、く→き、ぐ→ぎ、す→し、つ→ち、ぬ→に、ぶ→び、む→み、る→り. Look up only your group 1 verb's final kana. You do not need to learn new verbs for all nine endings now.
Notice 帰る（かえる）: its entry states group 1. Its る therefore changes to り, giving 帰ります. Compare 食べる from group 2, where る is removed. The same final written character does not tell you which operation to use.
読みます
飲みます
書きます
Group 3: two fixed changes
The two basic irregular verbs are する and 来る. Learn their complete pairs: する → します and 来る（くる） → 来ます（きます）. In 来る, the kanji 来 stays in place but its reading changes from く to き. The kana make that change visible.
A familiar verb ending in する follows the same pattern. In 勉強する, 勉強 stays and する becomes します: 勉強します. Do not apply the group 1 rule to its final る. The dictionary form helps you recognise which part stays unchanged.
します
来ます
勉強します
Putting the form back into a sentence
The verb you looked up now fits the sentences you already know. Choose the action, form its ます version using the stated group, then add the sentence blocks. For an action, the place takes で and the object often takes を: うちで + 水を + 飲みます.
The group does not change when you mean yesterday or negate something. Here, the stem is the part before the polite ending, such as 読み in 読みます. After forming the correct stem, use the four polite endings from the verb bridge. 読み + ました gives 読みました. Keep the decisions separate: first form the verb's stem, then choose the ending for time and negation. The final check stays with ます.
うちで水を飲みます。
学校で日本語を勉強します。