小黑叔叔平均每月发送彩信15条，如果按每条5角计费，他两个季度的彩信费用是

____元

阅读短文,判断正误。

    All the students in China are learning English, but how can they learn English well? Some students can know a lot about English, they can do some exercises, but perhaps they can't speak English loudly.

    If you want to know how to swim, you must get into the river. And if you want to be a football player, you must play football.

    So, you see, you can learn English by using (使用) it. You must listen to your teacher in class. You must speak English to your classmates everyday and also you must watch some English cartoons, sing some English songs, write some English diaries.... Then one day you may find you can speak very good English.

书面表达：

最近你发现我们学校很多学生的饮食存在很严重的问题，他们不吃早餐或其他正餐，而是选择一些垃圾食品。请根据以下提示写一篇英语短文。

1）阐述问题；

2）分析原因（学生喜欢吃垃圾食品、餐厅饭菜种类少等);

3）提出两个以上解决办法。注意词数120左右（开头已给出，但不计入总词数）。

参考词汇：餐厅 canteen

观察下列算式：

①1×5+4=3²，

②2×6+4=4²，

③3×7+4=5²，

④4×8+4=6²，

…

请你观察规律解决下列问题。