Even though he knew that his mother had been ill, he did not have the propriety to write her.

【正确答案】 A

【答案解析】propriety适当，得体，礼貌。decency合乎礼节，礼貌；体面；(言语、动作的)优雅。posterity后代，后裔，子孙。apathy冷漠，冷淡。eulogy颂词，悼词。