Complete the following statements:
$(i)$ Probability of an event $E +$ Probability of the event 'not $E$' $= \dots \dots \dots \dots \dots$
$(ii)$ The probability of an event that cannot happen is $\dots \dots \dots$. Such an event is called $\dots \dots \dots \dots \dots$
$(iii)$ The probability of an event that is certain to happen is $\dots \dots \dots$. Such an event is called $\dots \dots \dots \dots \dots$