He sits ____ his sister

He sits ____ his sister
A.next b.next to C.on D.over
用介词填空
Shall we meet ___ the gate of the school
Is he playing ____ the road or ____ the street
Are they ___ a factory or ____a farm
I sit ____the twins.The younger sister is ____my left and the elder one is ____my right
The big tree _____our classroom is nearly 100 years old