The French knows another form of reference to an unknown subject, which is on. Now the questions is when to use on and when to use il.
Examples
a)
Il faut aller à l' école.
One has to go to school.
b) On doit le faire.
One has to do it.
Even though there are some complicated details we first start with a simple basic rule: Il is used when there is no possibility of mixing with the male third person singular.On is used when this possibility is given. This means that mostly
il is used and on
only in case the danger of a mix-up is given.
Examples
Il
doit le faire.
He has to do it.
On
doit le faire.
One has to do it.
This is one example where on is to be used.
Examples
Il
vaut mieux ne pas le faire.
It is better not to do it.
NOT:
On vaut mieux, ne pas le faire.
There is no risk of a mix-up with the third person singular, therefore il is used.
