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。
It is imperative that students _____ their term papers on time.
YouthatlettertoJames.However，yodidn't（）.
At______,photographyisachemicalprocess,duringwhichalight-sensitivematerialisalteredwhenexposedtolight.
_____ if I had arrived yesterday without letting you know beforehand.