At the end of the month the Post Office will send him an enormous telephone bill which he will have to pay.
When I pass my driving test I will hire a car from our local garage.
When I was a child I did not understand adults, and now that I am an adult I do not understand children.
Can you stand on your head? - I could when I was at school but I cannot now.
I do not remember the address. - You even do not remember the street.
You are putting too much in your rucksack; you will never be able to carry all that.
When the fog lifts we will be able to undrestand where we are.
In the past times people were able to learn several languages at school.