56.
If you cross the line you will be disqualified.

57.
Why the dinosaurs died out is not known.

58.
His father won't be able to leave for Varnasi until they have arrived.

59.
I will not go to school, if it shall rain tomorrow.

60.
If I stood alone in defence of truth, and the whole world is banded against me and against truth. I would fight them all.