从方框中选择合适的单词，并用其正确形式填空。

    Jane is my good friend. She 1             from Canada. She speaks 2            . We are in the same class.

Many students in our class like English 3            , but I don't like it at all. My English is 4           , so she

often helps me 5            it. And I help her study Chinese. We help each other.

将3.42 g蔗糖与3.24 g淀粉混合并使其完全水解，若反应后生成m g葡萄糖和n g果糖，则n:m为 [ ]

A．1：3

B．3：1

C．1：5

D．5：1