______in their island community, the various tribes used languages which became more and more similar to each other.

【正确答案】 D

【答案解析】manage经营，设法对付；shrink收缩，退缩(shrink back退缩，害怕)；assume假设，担任(assume responsiblity承担责任)；isolate使隔离，使孤立，使脱离，一般指地理位置的孤立。根据句意判断，答案为D。