Grammar Notes for Dialogue 1
Grammar Note 1 Verb-stem に + motion verb (purpose)
 

In Lesson 10, we learned the expression かいものにいきます ("go shopping"). In this lesson, we will learn to use the same particle preceded by a coming and going verb in its verb stem form: /Verb-stem + に/. This structure can be combined with a motion verb to express a notion of "come/go somewhere for the purpose of V-ing" or "come/go to V."

The verb stem is a ます form of the verb minus ます. For example, ()べ is the verb stem of 食べます ("eat").

  V-stem Motion Verb  
おひるを () かえりました。 He went home to eat lunch.
本を () (本屋(ほんや)へ) 行きましょう。 Let's go (to the bookstore)
to buy books.
何を 来ましたか。 What did you come here for?
また あそび 来て下さい。 Please come to play again.

Compare this structure with the following /V1て+ V2/ pattern we learned in Lesson 18.

おひるごはんを 食べて かえりました。 He went home after eating lunch.
(Lit. "He ate lunch and went home.")

Caution: Verb stems are not the same as the Vて forms. The first sentence below is ungrammatical.

* おひるごはんを食べてにかえりました。[ungrammatical]
→ おひるごはんを食べにかえりました。[correct]

Grammar Note 2 Counting things in Japanese (まい, ほん, さつ, つ, こ, かい)
 

So far, we have learned counters to count money (円), telephone numbers (ばん), people (り/にん), age (つ/さい), hours (じ/じかん) and minutes (ふん), days (にち), months (がつ/かげつ), years (ねん), and so on. To count long cylindrical objects the counter (pronounced as ほん, ぽん, or ぼん) is used. Don't confuse this with the word for "book" also written as (ほん).

The counter まい is for thin, flat objects like paper; the counter さつ is for books and other bound objects; the counter is for small, solid objects. Note that books () is counted by the さつ counter, not the counter.

In Lesson 19, we learned that the counter can be used to count age from one to nine. The counter つ can also be used to count objects of indefinite shapes up to nine (9). ("Ten" is とお.)

本 counter

(long, thin objects)

まい counter
(thin, flat objects)

さつ counter
(bound objects)

こ counter
(small solids)

つ counter

indefinite shapes (or people's age)
(up to 9)

Grammar Note 3 Particle: に (for X)
 

The particle can express a similar sense of purpose as the English preposition "for" as in "for him" or "for breakfast" or "for his birthday."

あさごはん パンを食べました。
  I ate bread for breakfast.
先生のたんじょう()プレゼント はなを()いました。
  I bought flowers for the teacher's birthday present.
このセーター、はちょっと小さいです。
  This sweater is a little (too) small for me.
The last particle には is a combination of a purpose marker に and a contrastive marker は.