Undershirts were worn by European soldiers because.....
T-shirts were adopted by the U.S. Navy and Army as......
in the 1950s, Americans watching movies were shocked when......
The T-shirt was made a symbol of rebellious youth .....
Many variation of the T-shirt appeared in the 1960s because.....
In 1960s, the T-shirts became even more popular as a kind of merchandise when.....