1. He wrote this novel last year.

Question

1. He wrote this novel last year.

=> This novel was written last year.

2. He has written this novel in easy English.
=> This novel is written in easy English.

3. He lost two pens last week.
=> Two pens were lost last week.

4. He has lost two pens .
=> Two pens are lost (by him).

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Was the active voice sentence changed into passive voice sentence well?

Answer 1

All are fine.

If you want the complete meaning of the active sentence to be carried into the passive sentence, then "by him" needs to be in all of them. However, including that makes all except the last one rather awkward.

Answer 2

Yes, the active voice sentences were changed into passive voice sentences correctly. The subject of the active voice sentence became the object of the passive voice sentence, and the verb was changed to the corresponding passive form (e.g., "wrote" to "was written" and "lost" to "were lost").

Answer 3

Yes, the active voice sentences were changed correctly into passive voice sentences. In each case, the subject of the active voice sentence becomes the object in the passive voice sentence, and the verb is changed to its corresponding passive form. Additionally, the agent (the person or thing that performs the action) is omitted or can be added with the preposition "by" to indicate who performed the action in the passive sentence.