He had to wait FOR 15 MINUTES before we came(alternative).
His son will be in the sixth form next year(general)
We shall work HARDER next year(special)
My elder brother joined the air WHEN HE WAS 17(special)
I was looking at YOUR photos while you were out( special)
He hasn't done any work today(disjunctive)
He smokes a pipe after supper.(general)
He saw A NICE tie in the shop window( special)
The porter was hardly able to carry My LUGGAGE(special)

Did he have to wait for 15 minutes  or for 20 minutes before we came?will his son be in the sixth form next year?How shall we work next year?When did your brother join the air?Whose photos was i looking while you were out?He hasn`t done any work today, has he?Does he smoke a pipe after supper?What tie did he see in the shop window?What was the porter hardly able to carry?