根据中文提示和英文书信内容，写一封意思连贯、符合逻辑、不少于60词的回信。信的开头和结尾已给出，其词数不计入所完成的回信内。请不要写出你的校名和姓名。

假设你叫李华，是美国中学生爱丽丝的笔友，你收到了她的电子邮件。请给她回复，回答她的问题，提出你的建议，并就此事谈谈你的看法。

用am，is或are填空，然后总结其用法。

(1)That's my father and this ________ my mother.

(2)This is my cousin and that ________ my sister.

　　(3)－________she your sister?

　　－Yes, she ________.

　　(4)－And ________ he your brother?

　　－No. He's my friend.

　　(5)－________ Guo Peng your brother?

　　－Yes, he ________.

(6)I ________ his friend. I'm not his brother.

　　(7)－________ you Jack's brother?

　　－No, I'm not. I ________ his cousin.

(8)These ________ my grandparents.

　　(9)－________ this your aunt?

　　－Yes, it ________.

(10)These ________ my parents, those ________ my grandfather and grandmother.

(11)These are my brothers. They ________ Jeff and Jack.

(12)They aren't my sisters. They ________ my friends.

am用于第一人称单数I之后；is用于第三人称单数ge，she，it以及相当于he，she或it；are用于第二人称或所有人称的复数，表达“是”的意思。可用下面的口诀来帮助记忆：“我用am你用are，is用于他她它，复数全都要用are”。

I am…可以缩写成I'm，he is可以缩写成 he's，she is可以缩写成加she's，it is可以缩写成it's，而we are，you are，they are可分别编写成we're，you're，they're。am，is，are的否定形式是在后面加not，如：am not，is not，are not。is not通常缩写为isn't，而are not通常缩写为aren't。如：

(1)I'm Alice, I'm not Mary. She's Mary.

(2)This isn't my brother. He's my cousin.

(3)They're my brothers. They aren't my friends.

--- What’s the matter, Mary? You looked upset.
--- I failed again in my math exam. I’m really sorry because I don’t want to ____ my parents down.

Tomorrow is Saturday. I’m not going to work, and my brother isn’t going to school. We are going to play table tennis. We are going to have lunch in a restaurant. We’re coming home at five. My parents are going to visit my grandparents. They are going to get home at half past five. We are going to help my mother cook the dinner. After supper, I am going to dance with my friends, and my brother is going to watch TV with my parents.
【小题1】What day is it today?