1. He wrote this novel last year.

Question

=> 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.