Students are sitting lined up on stair steps while they wait and check their electronic devices .
It is probably the case that some people are seated in order and are looking at things in their hands .
It is probably the case that some people are seated in order and are looking at things in their hands .
There is little chance that some people are seated in order and are looking at things in their hands .
Some people are seated in order and are looking at things in their hands .