Are my parents often invited by their friends to the country? (General)
Who are often invited by their friends to the country? (Special)
Whose parents are often invited by their friends to the country? (Special)
Where are my parents often invited by their friends (special)
By whom are my parents often invited to the country? (Special)
How frequently are my parents invited by their friends to the country? (Special)
Are my parents often invited by their friends to the country? (General)
Who are often invited by their friends to the country? (Special)
Whose parents are often invited by their friends to the country? (Special)
Where are my parents often invited by their friends (special)
By whom are my parents often invited to the country? (Special)
How frequently are my parents invited by their friends to the country? (Special)