We wished … good luck before the exam.
I can’t see … in the mirror.
Why doesn’t he wash the cup …?
It’s very delicious! Did you invent the recipe…?
My granny knits all her socks and scarves ….
The zebra can’t defend … .
Are they going to Moscow by …?
Вставьте возвратные местоимения.

1. We wished ourselves good luck before the exam.
To form this sentence correctly, the appropriate reflexive pronoun is "ourselves." The subject "we" is wishing good luck to themselves.

2. I can’t see myself in the mirror.
In this sentence, the reflexive pronoun "myself" is used because the subject "I" cannot see his/her reflection in the mirror.

3. Why doesn't he wash the cup himself?
The reflexive pronoun "himself" is used in this sentence to emphasize that the subject "he" should wash the cup on his own without relying on someone else to do it.

4. It's very delicious! Did you invent the recipe yourself?
The reflexive pronoun "yourself" is used to inquire if the subject "you" created the recipe independently without anyone else's assistance.

5. My granny knits all her socks and scarves herself.
In this sentence, the reflexive pronoun "herself" is used to emphasize that the subject "my granny" knits all her socks and scarves without help from others.

6. The zebra can't defend itself.
The reflexive pronoun "itself" is used in this sentence because the subject "the zebra" is unable to protect itself without assistance from others.

7. Are they going to Moscow by themselves?
The reflexive pronoun "themselves" is used to ask if the subject "they" are planning to go to Moscow without anyone accompanying them.

Таким образом, ответы с вставленными возвратными местоимениями должны быть следующие:
1. We wished ourselves good luck before the exam.
2. I can't see myself in the mirror.
3. Why doesn't he wash the cup himself?
4. It's very delicious! Did you invent the recipe yourself?
5. My granny knits all her socks and scarves herself.
6. The zebra can't defend itself.
7. Are they going to Moscow by themselves?