【正确答案】 A

【答案解析】[解析] unlikely意为“不大可能的 (not likely to happen)”，表示说话人认为某事将来不大可能发生，或者认为不大可能成为事实，由它引出的主语从句的谓语动词应用将来时，例如：That he will refuse the offer is unlikely. 他拒绝这项建议的可能性不大。It is unlikely that enough workers will be found if there is no substantial improvement in salaries and working conditions. 如果工资不大幅度增加，工作条件得不到改善，就不大可能找到足够的工人。所以，该题只能选A项。