题目

—_____ does he meet his friends? —_____ a month. A. How often; Twice                    B. How long; Twice C. When; Two                       D. What time; Two   答案：A17．已知一盒奶酪共15个，甲老鼠吃了这盒奶酪的$\frac{1}{3}$，乙老鼠吃了这盒奶酪的$\frac{2}{5}$，问谁吃的多．