“干冰”的粉末常用在舞台上制造云雾缭绕的幻境，“干冰”能产生白雾是因为[ ]

A．干冰挥发出大量的水蒸气

B．干冰能产生大量的白色二氧化碳气体

C．干冰易升华，吸收大量的热，使空气中的水蒸气冷凝

D．二氧化碳可溶于水，形成了大量酸雾

We didn’t know how to find them because they didn’t tell us _______.

A．which room did they live

B．which room they lived in

C．which room they lived

D．which room did they live in