Mary spent half ____ hour doing ____ work.A.a;an B.an;a C.a;the D.an;the

Mary spent half ____ hour doing ____ work.A.a;an B.an;a C.a;the D.an;the Mary spent half an hour on play the piano 这句话不对吗?应该怎么该? I spent three and a half hours doing my work.(改同义句)I spent ____ ____ ____ ____ ____ doing my work. We spent half an hour writing it.(提问）____ ____ ____ you ____ writing it?(___代表空格） He spent half an hour on the newspaper yesterday (改为同义句)He ____ half an hour ____ the newspaper yesterday Mary spent three thousand yuan on the color TV set.The color TV set ____ ____ three thousand yuan It ____ them one and a half days ……这里怎么判断是用cost还是spent I spent half an hour_______my book. it ____（spent/took/cost/paid)the workers half a year to build the bridge.选择,要过程不需要改变单词形式 close to 与 closing toThey spent ____ half a million dollars in building the bridge.A close to B closing to 答案是A ,为什么啊? I spent half an hour ___(finish) my homework. I spent half an hour in doing my homework i spent half an month reading the book什么 He spent half an hour___computer games yesterday everyonekkkk they spent half an hour on talk是什么基本句型 We spent half an hour writing it.(%u63D0%u95EE%uFF09 Life is half spent before we know what it is. Life is half spent before weknow what it is