Click student's name in gradebook
To look at a particular student's activity in the course as a whole, first click on the student's name in the gradebook.
View scores and date submitted
From the screen below, you can see the particular student's score and date submitted for every assignment in the course (if there is no score/date submitted, then the student has not completed the assignment).
View student's time spent on each activity
To look at the complete activity of the student by minutes, click the Activity icon at the top right.