A strange feature of the umbrella' s use is that it was used as （）

A．No one exactly knows who was the inventor of the umbrella.
B．The umbrella was first invented to be used as protection against the sun.
C．The umbrella changed much in style in the eighteenth century.
D．In Europe the Greeks were the first to use the umbrell

A．when and how the umbrella was invented
B．why the umbrella was so popular in Europe
C．the development of the umbrella
D．the history and use of the umbrella