单选题 When ______,ice will be changed into water, or even steam.
A) heated C) to heat
B) heating D) be heating

【正确答案】 A
【答案解析】主语ice与动词heat构成被动关系，即“冰被加热”。故分词需用过去分词，表示被动。句意：冰块加热时会变成水甚至蒸汽。