关于借记卡年费，以下说法错误的有（）
A、主卡10元
B、附卡5元
C、金卡30元
D、钻石卡0元
参考答案：C
根据上下文意思写出句子中单词所缺的字母。
1. Fifty m________ thirty is t________.
2. Q________ to e________ means 7:45.
3. We eat m_________ in Mid-Autumn Festival.
4. Classes begin at 9:00. Janet gets to school at 8:45. She is n________ late f________ school.
5. Teacher's D________ is on 10th S ________.
设方程
有无穷多个解，则a=______．
有无穷多个解，则a=______．