The boy often helps the old man_____(运)water and sweep the f

The boy often helps the old man_____(运)water and sweep the floor.
It gives me great p____to introduce our speaker this evening.
The boy wants a new car,But his mom turns a d___ ear to his wishes.
We saw a d___vehicle(车辆) on the side of the road.
请说明理由!
请尽快!