American ingenuity and science are constantly ________ improving
分类: 基础英语(00088)发布时间: 2024-08-26 05:30浏览量: 1
American ingenuity and science are constantly ________ improving the quality of products. A、for work B、with work C、at work D、in work 【正确答案】：C 【题目解析】：be at work起作用 句意：美国人的聪明才智和科学不断提高产品的质量。