Four-line writing formula pinyin grid, four lines, pinyin letters live in it. Living in the last place is better than not stepping on the line in lower case letters and writing on both sides of the top in lower case letters.

Open your mouth, aaa2. Round mouth, ooo3. Flat mouth, eeea, o, e nursery rhyme: 00 cock crows, my aunt takes me to the west of the village.

Little white goose, ee barks, as if to say "good morning!" Go all out, iii:5. Protruding mouth, uuu:6. Whistle, uuu.i, u, u.

Children's song: Little ant, it's going to cross the river. Uncle Tortoise carries it on his back, and the fish laughs when he sees it.