Ask questions about the sentence: the head teacher proposed that we come to his school for 15-20 days in april. how ? !

Did the Head Teacher propose that we come to his school for 15-20 days in April?
Who proposed that we come to his school for 15-20 days in April?
Where did the Head Teacher propose that we come to for 15-20 days in April?
When did the Head Teacher propose that we come to his school for 15-20 days?
How long did the Head Teacher propose that we come to his school in April?