請病假 的英文怎么说?

[1] take a medical leave (of absence) (from work)[2] to go on medical leave
  to go on sick leave[3] call in sick[4] take a sick day[5] on sick leave
  on medical leave[6] be out sick

take a medical leave 是很正統的英語說法，可用在一天或多天的病假，算是比較正式的英文。

to go on medical leave = to go on sick leave = 請病假，通常是指請很多天的病假，但即使請一天也能使用

take a medical leave = take a medical leave of absence = take a medical leave of absence from work

"他今天請病假" 可說:

He called in sick today.
He is taking a sick day today.
He is on sick leave today.
He is on medical leave today.
He's out sick. (最簡單的說法)