Brainliest+excellent rate+thanks =
For you
When you follow instructions given with the question
Instructions:
1.you can write with help of researching the answer in Google or various websites.(not compulsory as the wishes of the writer)
2.answers should me mentioned with question numbers(compulsory)
3.very thing you write should be clear

Question:
A.Rewrite the following sentences in passive voice.
1.they have lost their luggage at the airport.
2.close the window.
3.turn off the television.
4.who switched on the lights?
5.children ought to respect their elders.
6.the students should have learnt the poem.
7.this work was to be done by Atul.
8.they are climbing the ladder.
9.we are celebrating my parents' Silver Jubilee.
10. Mrs. Leela cut the ribbon at the inauguration.
11.you must invite her
12.turn off the fan.

In order to convert a active voice into passive voice we must Identify the subject followed by the object and Main verb in the given sentence and then swap object instead with subject and also the subject with object.
Now we should convert the main verb into its third form and finally add a helping verb of "to be"

Now the given active voice sentence and converted into passive voice:

1) Luggage was lost by them at the airport.

2) Let the window be closed.

3) Let the television be turned off.

4) By whom the lights were switched on.

5) Elders must be respected by the children.

6) The poem should have been learnt by the student.

7) Atul was supposed to do this work.

8) The ladder is set to be climbed by them.

9) My parents Silver Jubliee was celebrated by us.

10) The ribbon at the inauguration was cut by Mrs. Leela.

11) She must be invited by you.

12) Let me fan be turned off.