We should've set the alarm for 7:30.
我们应该把闹钟定到七点半的。

should have done
本应该做某事（却没做）

set the alarm for..+时间
把闹钟设在（几点）
I should've come early.
我应该早点来的。

I should've accepted that.
我本应该接受的。

A:What time is it?
几点了？
B:8:50(ten to nine)
8点50（九点差十分钟）
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.
你的表慢了十分钟，所以应该是九点整了。我又要迟到了。这次我要找什么借口？我们应该把闹钟定到七点半的。
B:Don't cry over spilt milk.Fred,could you stay with me a few more minutes?
不要做无用的后悔了。费雷德，你能和我再呆上几分钟吗？
A:What?Why?What's wrong with you?
什么？为什么？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?
我只是讨厌一个人呆在家里听着钟表滴滴哒哒，无事可做。好孤单好无聊啊。再加上我现在生病，就更糟了。我什么时候才能好啊？
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.
两三个月后你就会好的。耐心点。我现在得去工作了。不然要迟到了。
B:You only care about your work.
你只关心你的工作。
A:Sorry,honey.You're everything to me.All I do is for this family.
对不起，亲爱的。你才是我的全部。我所做的一切都是为了这个家啊。
B:Stay just a few minutes longer,okay?
就再待几分钟，好吗？
A:Ok.I'll leave at 9:15.Is that all right?
好的。我9点一刻出门，这样行吗？