【题目】When we saw the road _____ with snow, we decided to spend the holiday at home.
A.block
B.to block
C.blocking
D.blocked

【答案】D
【解析】句意：当我们看到雪封路的时候，我们决定在家度假。此处非谓语动词作宾补，动词block与see的宾语the road之间为被动关系，构成短语see sb/ sth done。故选D。