13. I'm always tied up with my work.
我总是忙得不可开交。
还能这样说：
I always have my hands full.
I am on the go.
应用解析：
tie sb. to work 工作缠身；
tie sb. hand and foot 捆住某人的手和脚，使某人不能行动自如；
tie oneself in knots 结婚；
tie in with sth. 有某事一致或有联系

14. I don't even have time to catch my breath.
我连喘气的机会都没有。
还能这样说：
I don't have any chance to take a break.
I have no time to rest.
应用解析：
knock the breath out of sb. 使某人大吃一惊；
take breath 歇息；
waste one's breath 白费口舌；
speak under one's breath 低声细语；
save one's breath 不做声，沉默

15. Could you stay late?
你能晚点儿下班吗？
还能这样说：
Could you work overtime?
Could you leave here for exra work?
应用解析：
be here to stay 被普遍接受；
stay one's anger 息怒；
stay clear of sth. 避免涉及某事；
stay put 待在原地，固定不动

16. Don't work too hard.
别过度劳累。
还能这样说：
Don't be overtired.
you'd better not work too tired.
应用解析：
be hard done by 亏待，苛待；
die hard 习惯不易根除；
hard at it 竭尽全力；
as hard as nails 冷酷无情，铁石心肠的；
hard facts 客观事实