My daughter won't be at school until the second period today because I have to take her to the hospital.
「◯時間目」は英語で次のように言います。
1時間目ーfirst period
2時間目ーsecond period
3時間目ーthird period
4時間目ーfourth period
5時間目ーfifth period
6時間目ーsixth period
例:
My daughter won't be at school until the second period today because I have to take her to the hospital this morning.
「今朝娘を病院に連れて行かなければいけないので、今日は2時間目から登校します」
won't be at school until the second period「2時間目まで学校にいない」ということは「2時間目からいる」と言えますね。
ご参考まで!