题目

Central Park covers more than three hundred and forty hectares（公顷）. It was the first public park built in the United States. In 1858, a design competition was held to find the best idea for planning the huge area in the center of New York City. The winners were two landscape designers, American Frederick Law Olmsted and Calvert Vaux from Britain. It was not easy to create this park. It may look like a natural environment of lakes and woodlands, but it was entirely built by human labor. Workers moved millions of cubic meters of stone and earth to clear the area. They brought in m多酶片中含有的蛋白酶、淀粉酶、脂肪酶具有辅助消化的作用。关于酶的叙述，正确的是A．多酶片中的酶都是蛋白质　　　　　B．一个酶分子只起一次作用C．酶提供反应开始时所必需的活化能　　D．食物消化过程需要酶的作用,而细胞内的化学反应不需酶的作用