单选题 The timber rattlesnake is now on the endangered species list, and is extinct in two eastern states in which it once______.
A. thrived B. swelled C. prospered D. flourished

【正确答案】 A
【答案解析】[解析] A项thrived意为“兴旺；茁壮成长”；B项swelled意为“膨胀，肿胀”；C 项prospered意为“发达”；D项flourished意为“茂盛；盛行”。