I don't know who invented ________ iphone,but I think it is ________ useful invention.
If by any chance someone comes to see me, ask them to have a __________.
They were surprised that a child should work out the problem ________ they themselves couldn't.
Mary has _______ a difficult question to me.
To the sea captain's surprise, he found that ________ travel could also be quite pleasant.
A piece of ________ music will make you happy.