题目

At a beautiful beach a little boy on his knees packs the sand into a bucket He turns the bucket upside down and______it. To the______of the little architect, a castle tower is created. He works all afternoon packing the walls building sentries( 5E)with bottle tops and bridges with sticks. And a sandcastle will be built.In a big city with _____streets and traffic, a man works in an office. He packs papers into piles, holds the phone between his______and shoulder and______the keyboard with his fingers. Contracts get signed and to the joy of the man, a _____is made. His pension will be sentries a_______ are playing an important part is well known to us all.A.That whoB.Those whoC.Who thatD.Who