Changing sentences from declarative to interrogative involves rephrasing them to form questions. Here's how to convert each given sentence:
She wakes up in the morning. Interrogative: Does she wake up in the morning?
Mohan went to the market yesterday. Interrogative: Did Mohan go to the market yesterday?
You will work tonight. Interrogative: Will you work tonight?
She sang a song. Interrogative: Did she sing a song?
Ram has gone to school. Interrogative: Has Ram gone to school?
We have seen the film. Interrogative: Have we seen the film?
I bought apples last night. Interrogative: Did I buy apples last night?
My mother will cook delicious food. Interrogative: Will my mother cook delicious food?
We go to Delhi. Interrogative: Do we go to Delhi?
I had eaten food. Interrogative: Had I eaten food?
He was learning his lesson. Interrogative: Was he learning his lesson?
They will leave a trip. Interrogative: Will they leave for a trip?
She will have written a letter. Interrogative: Will she have written a letter?
The Stranger grabbed his arm. Interrogative: Did the stranger grab his arm?
In constructing interrogative sentences, one often uses auxiliary verbs like 'do', 'does', 'did', 'will', 'has', and 'was'. These are placed at the start of the sentence, followed by the subject and the main verb. This change helps in making sure the sentence forms a question.