小学用be动词的适当形式填空(急)

小学用be动词的适当形式填空(急)
小学练习题上的,我英语特别差,能注上为什么这么填更好,
1.I( )at school just now.
2.He( )at the camp last week.
3.WE( )students two years ago.
4.They( )on the farm a moment ago.
5.Yang Ling( )eleven years old last year.
6.There( ) an apple on the piate yesterday.
7.There( )some milk in the fridge on sunday
8.The phone( )on the sofa yesterday evening.
怎么都不一样的答案啊,到底哪个是正确的,可信点的有吗