I would like to know if I could ask for a casual leave of absence for (寫上妳要請假的天數) day on （寫上要請假的具體日期）, （表明是周幾）.
The reason for my absence is that my wife is pregnant and I have to company her to go to hospital to do the antenatal care.
Concerning my workload: As (寫上請假的那天是周幾) is not as busy as the other weekdays, I think a one-day leave this 周幾 may be the best solution. I apologize for the inconvenience my absence from work may cause.
Thanks. I will call you at (寫上妳想要得到老板的答復的時間). or you can call me at any time.
希望能夠幫到妳，如果妳是要寫電郵的話，還要註意電郵的格式，大致如下：
To：假條是遞給誰的
From：請假人
Date：寫假條的日期(註意不是請假的日期)
Subject：寫上請假字樣