Linking devices are used to link one idea or argument to another. A common situation is when we are talking about something that happens and its result, or a cause and its effect.

http://www.bbc.co.uk/learningenglish/english/course/intermediate/unit-10/session-2/activity-3

http://www.bbc.co.uk/learningenglish/english/course/intermediate/unit-25/session-2/activity-3

http://www.bbc.co.uk/learningenglish/english/course/upper-intermediate/unit-30/session-1

http://www.bbc.co.uk/learningenglish/english/course/towards-advanced/unit-4/session-1