题目

—Could you tell me how to improve spoken English? —Well, just take every chance to practice ________ and don’t be shy. A. speak                     B. to speak               C. speaking                 D. spoke 答案：C儿童患佝偻病，是由于缺乏哪种无机盐造成的A．含磷的无机盐B．含钙的无机盐C．含铁的无机盐D．含碘的无机盐