A.
Whether the German engine was the first to fly is not clear.
B.
He asked whether or not I wanted to insure my luggage.
C.
The question is whether they will take our advice.
D.
The question whether he will come is unknown.
E.
I don't know whether they will come to help us.
F.
It depends on whether it will rain.G . The teacher will tell us whether to have the exam next week.