题目

In order to gain a bigger share in the international market, many state-run companies are striving _______ their products more competitive. A. to make                 B. making                   C. to have made    D. having made 答案：A 解析: 不定式作目的状语。“使产品更具竞争性”是“正在努力的目的”。黄铜是生活中常用的金属材料，它是铜和_______的合金（填名称）。