America has more than fifty states, ______, Kentucky, is the place _______ Abraham Lincoln was born.
.Among all the problems,_______is so difficult as this one.
It was 1920 ______ regular radio broadcasts began.
_____ is reported in the newspaper that talks between the two countries are making progress.
Have you any knives? I need a sharp ________.
Lucy has a great sense of humour and always keeps her colleagueswith her stories.