单选题 Morality without religion is unthinkable for religion is to morality ______ water is to seeds in the soil.
A. when B. that C. which D. as

【正确答案】 D

【答案解析】该题中as是表示比较关系的连接词，意思是没有宗教的道德是不可思议的，因为宗教之于道德犹似水于土中的种子，该句中还可以用what这个连接词，形成A is to B as (what) C is to D这样的句式。