8.Nam asked his friend whether her/his sister and brother went to the same school.

asked sb+to V

9.The photographer told him to give him a smile.

10.My teacher told us not to discuss that question then.

told sb+not to V

11.She said if the weather was fine, she would go on a picnic with her friends.

8. Nam asked his friend if his/her sister and brother went to the same school

9. The photographer asked him to give him a smile

10. my teacher asked us not to discuss that question then

11. She said if the weather was fine, she would go on a picnic with her friends

Giải thích:

Lùi thì 

HTĐ > QKĐ

QKĐ > QKHT

...

Chuyển đổi adv (nếu có)

now > then

Chuyển đổi chủ ngữ, tân ngữ thích hợp

Đối với câu điều kiện loại 1,0 thì lùi thì còn loại 3,4 không phải lùi, loại 2 vế if mới lùi