Simple Past or Present Perfect
By the time I'm 80 I ___________(retire)
will have retired
(a finished action in the future)
When I'm older I ______ (study) in a foreign country.
will study
(a prediction/plan)
Before the age of 40 my friend ___________(become) a millionaire.
will have become
(a finished achievement in the future)
At the end of class I _______ (switch off) the computer.
will switch off
(at = used to begin an action)
By the end of class, I ________(practice)
(by = used for the end of an action)