单选题 Before the building project is designed, ______ data have been collected for it.

【正确答案】 D
【答案解析】难词辨义。原句意为:在这项建筑工程设计之前已经收集了充分的资料。persistent意为“坚持的,持久的,”appropriate意为“适当的,”thoughtful意为“沉思的,考虑周到的,”sufficient意为“足够的,充分的,能胜任的。”如:He has sufficient income for a comfortable retirement他有足够的收入保证了舒适的退休生活。