一筆不苟〔-笔--〕 jat¹ bat¹ bat¹ gau² {yī bǐ bù gǒu}

1. lit. not even one stroke is negligent (idiom)
2. fig. to write characters (calligraphy) in which every stroke is placed perfectly

一筆抹殺〔-笔-杀〕 jat¹ bat¹ mut³ saat³ {yī bǐ mǒ shā}

1. to blot out at one stroke
2. to reject out of hand
3. to deny without a hearing

一筆勾銷〔-笔-销〕 jat¹ bat¹ ngau¹ siu¹ {yī bǐ gōu xiāo}

to write off at one stroke

一筆還一筆〔-笔还-笔〕 jat¹ bat¹ waan⁴ jat¹ bat¹ {yī bǐ hái yī bǐ}

one account apart from one account, it means to separate one event from another instead of combining them together