多选题 The attempts of epidemiologists to ______ the infectious disease ultimately proved futile: as soon as they managed to ______ it in one community, it would emerge somewhere else.

A、 contain
B、 replicate
C、 defend
D、 extend
E、 check
F、 unleash

【正确答案】 A、E

【答案解析】[解析] ●冒号说明前后同义重复。
●两空联动，同义重复。
●contain遏制，replicate复制，defend保护；extend扩张，check抑制，unleash释放。答案选AE。