im those days john with his classmates (was/were)kept busy preparing for the exam.选那个?

填写：was
解析：在sb with sb 结构中,谓语动词的选择根据就远原则,即看with前面的名词或代词的单复数来判断,例如：1.My friends with I often go to play ball after class.
2.I with my mother go to see my grandpa once a week.
3.Tom with his mother is going to have a trip this weekend.
4.I with my sister am going to do some shopping this aftenoon.