词汇语义题。根据艾中“Right now,we don’t have a solution on how to combat it,so we’retrying to do some different things than what has happened before”，可知combat在这里是指“抵抗，战胜疾病”之意，所以正确答案是C；选项A(回来)、选项B(联合，混合)、选项D(避免)都不合题意。