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。
______isnotaseriousdisadvantageinlife.
If a substance is dissolved in water or heated ， it may （）a gas.
If you _____ in such a hurry,you _____ sugar into the sauce instead of salt.
Thebackgardenofourhousecontainsalawn，（）verypleasanttositoninsummer.