第22题: [单项选择]The language experts believe that the______age for learning a foreign language is 6 years old. A. conceptual B. considerate C. optimal D. component 参考答案:C 答案解析:[解析] optimal“最佳的,最理想的”符合句意。而conceptual“概念上的”;considerate“考虑周到的”;component“组成的,构成的”都不正确。