timestamp,action_type,item_id,source,user_answer,platform
1567147108108,enter,b7922,tutor,,mobile
1567147199749,respond,q10645,tutor,d,mobile
1567147212397,submit,b7922,tutor,,mobile
1567147212492,enter,e7922,tutor,,mobile
1567147230725,quit,e7922,tutor,,mobile