Here are the sentences rewritten in the negative and interrogative forms:
Negative Form:
Sujala has not lost the key to her room.
Mr. Shrestha had not understood the problem.
They had not shifted the luggage to their new house.
We shall not have finished the sums before evening.
Harsh has not forgotten to bring the money.
The teacher will not have corrected the papers by tomorrow.
The doctor has not brought the first-aid box.
The police had not arrested him before the end of the month.
The river has not overflowed its banks.
The computer had not shown incorrect results.
Interrogative Form:
Has Sujala lost the key to her room?
Had Mr. Shrestha understood the problem?
Had they shifted the luggage to their new house?
Shall we have finished the sums before evening?
Has Harsh forgotten to bring the money?
Will the teacher have corrected the papers by tomorrow?
Has the doctor brought the first-aid box?
Had the police arrested him before the end of the month?
Has the river overflowed its banks?
Had the computer shown incorrect results?
In the negative form, "not" is added to the auxiliary verbs (such as "has," "had," "shall," "will") to create the negative meaning.
In the interrogative form, the word order is changed, and the auxiliary verbs are placed at the beginning of the sentence.