We were swimming in the lake__________suddenly the storm started.

A．when

B．while

C．until

D．before

Flags have existed for over 3000 years. The earliest flags were wooden or metal poles topped with a carving. About 2000 years ago pies of fabric were added to some poles for decoration. Over the next 500 years the free-flying part of the flag became more important.

Every country today has its own flag. Many groups and organizations also have a flag which stands for, or symbolizes, the aims of the group.

The flag depicts (描绘) a world map, centered on the north pole. The map is surrounded by an olive (橄榄) wreath (花环) symbolizing peace and co-operation. The flag is blue and white.

小题1:Flags have been in existence for _________.

A．500 years

B．more than 3000 years

C．about 2000 years

D．between 500 and 2000 years小题2:A very old flag is likely to _________.

A．be made of fabric

B．have a map on it

C．have white shapes on it

D．be made of carved wood小题3:An olive wreath is used to stand for _________.

A．peace

B．purity

C．justice

D．equality