听力资源简介：

Dialogue 5 
(between customer and repairman)

Laurance- How long do you think it'll take to fix it?
Soony- Hard to tell. Sometimes we can find the problem
right away and sometimes it may take an hour or
two.
Laurance- Should I wait or come back later?
Soony- Suit yourself, but it's probably better to come
back later.
Laurance- You will get it fixed today, won't you?
Soony- I don't see any problem. We should have it ready
for you by three at the latest. But, better call
before you come.
Laurance- Okay. Thanks a lot.

注解:
suit yourself=do as you please
by three at the latest=not later than three o'clock,类似的短语还有:
at the most/at the earliest/at the least/at the best/at the worst 等.