We should've set the alarm for 7:30.
我們應該把鬧鐘定到七點半的。

should have done
本應該做某事（卻沒做）

set the alarm for..+時間
把鬧鐘設在（幾點）
I should've come early.
我應該早點來的。

I should've accepted that.
我本應該接受的。

A:What time is it?
幾點了？
B:8:50(ten to nine)
8點50（九點差十分鐘）
A:Your watch is 10 mintues slow,so it should be 9:00(nine sharp).I'm gonna be late again.What will my excuse be this time?We should've set the alarm for 7:30.
你的表慢了十分鐘，所以應該是九點整了。我又要遲到了。這次我要找什么借口？我們應該把鬧鐘定到七點半的。
B:Don't cry over spilt milk.Fred,could you stay with me a few more minutes?
不要做無用的后悔了。費雷德，你能和我再呆上幾分鐘嗎？
A:What?Why?What's wrong with you?
什么？為什么？你怎么啦？
B:I just hate being alone at home with nothing to do but listen to the clock ticking.It's so lonely and boring.My sickness makes it worse.When will I recover?
我只是討厭一個人呆在家里聽著鐘表滴滴噠噠，無事可做。好孤單好無聊啊。再加上我現在生病，就更糟了。我什么時候才能好啊？
A:You'll be fine in a couple of months.Just be patient.I've got to go to work now or I'll be late.
兩三個月后你就會好的。耐心點。我現在得去工作了。不然要遲到了。
B:You only care about your work.
你只關心你的工作。
A:Sorry,honey.You're everything to me.All I do is for this family.
對不起，親愛的。你才是我的全部。我所做的一切都是為了這個家啊。
B:Stay just a few minutes longer,okay?
就再待幾分鐘，好嗎？
A:Ok.I'll leave at 9:15.Is that all right?
好的。我9點一刻出門，這樣行嗎？