Question Detail

Someone has stolen his book.

His book is been stolen.
His book has been stolen.
His book is stolen.
His book has stolen.

Answer: Option B

Explanation:

Apart from Rule to make active voice of Present Perfect Tense, which is

Passive subject + has/have + been + third form of verb + by + passive object

Please also note that words like, "someone", "somebody", "people", "police", "public" etc are dropped. But in rare cases we can use them if sentence meaning is not clear.

1. Nobody can catch him.

He can not be caught.
He can not caught.
He could not be cought.
He could not cought.

Answer: Option A

2. They may win the battle.

The battle may be win.
The battle may be won.
The battle may be won by them.
The battle may won.

Answer: Option B

3. We must have obeyed our teachers.

Our teachers might have obeyed.
Our teachers might have been obeyed.
Our teachers must have been obeyed.
Our teachers must have obeyed.

Answer: Option C

Explanation:

If we have "Subject + Modal Auxiliary verb + have + third verb + object"
then we change it to

Passive subject + Modal Auxiliary verb + have been + third form + by + passive object.

Modal Auxiliary verb are : can, could, shall, will, may, might, should, would, must, ought to etc.