1 задание - везде вставляешь is, кроме 7 предложения, там будет are
2 задание
1. My brother is a student. He is at school.
2. Is your mother at home? -- No, she is at work.
3. Is your cousin at home? -- No, he is at school. He is a student.
4. Is your sister a teacher? -- No, she is a student.
5. Is your father at work? -- No, he is at home.
6. Is your sister a typist? -- Yes. -- Is she at home? -- No, she is at work.
7. My grandfather is a doctor.