英文题，要理由的。

1.____ most children here live _____most happy life.

  A./,/   B.the,the  C.the,a  D./,a

2.She came from____United states,she has been in____China for three year.

  A.the,/  B./,/  C.the,the  D./,the

3.In order to make it clear,I must go up to ____second floor and ask him___second floor.

  A.the,a  B.the,the  C.a,the  D.a,a

1.D

2.A    因为United states是专有名词，所以前面要加the。 has/have/had been in+地名（固定搭配）

3.A    因为second是序数词，所以前面要加the。