1. sever ties – to completely end a relationship.
2. round-the-clock - 24 hours a day.
3. not going to fly – this means that a solution isn't effective or that something
won’t work. If it’s an idea or a project, for example, you could also say that it
‘doesn’t have legs’.
4. in the black - means that a company is making a profit.
5. hands are tied – when you do not have any control over a situation. 

*Dispones de más Ejercicios de Inglés Comercial y de Negocios
con respuesta para practicar.