He set up in business____his own and was very successful.
C
「句意」他独自一人开始经商，并且做得很成功。
「难点」onone‘sown是个常用的介词词组，意为“独自”;ofone’sown表示“某人自己的(东西)”，如：Ihaveaflatofmyown.我自己有套房子。
You____thatlettertoJames.However，youdidn't.
Thecompositionscontainedsofewerrorsthattheteachergotthestudents_____oneanother’spapers.
Josephwasverylucky（）withhislife;healmostdidnotgetoutoftheroom.