36.These artificial flowers are made of silk.

⇒They make these artificial flowers of silk.                        

37. The lessons are being written by the students now.

⇒The students are writing the lessons now.
39.These animals at the zoo are fed twice a day.

⇒They feed these animals at the zoo twice a day.               
40. The operation is going to be performed by French doctors.

⇒French doctors are going to perform the operation. 
42. When was this radio manufacture?
⇒ When did they manufacture this radio?
43. They couldn't be found anywhere.
⇒People coulgn't find they anywhere.
44.Is mathematics taught in this school?
⇒Are they teach mathematics in this school?
45. Fortunately the machinery wasn't damaged by the accident.
⇒The accident didn't damaged the machinery fortunately.
46.Please wait here while your luggage is being examined?
⇒Please wait here while they is samining you luggage?
47.How are candles made ?
⇒How do they make candles?

36.These artificial flowers are made of silk

They make these artificial flowers of silk.                        37.The students are writing the lessons now
39.They feed these animals at the zoo twice a day.                41. All the arrangements have been made.
40.  French doctors are going to perform the operation.                          
42. When was this radio manufacture?
= when did they manufacture this radio?
43. They couldn't be found anywhere
= people coulgn't find they anywhere
44.Is mathematics taught in this school?
= are they teach mathematics in this school?
45. Fortunately the machinery wasn't damaged by the accident
= the accident didn't damaged the machinery fortunately
46.Please wait here while your luggage is being examined?
= please wait here while they is samining you luggage
47.How are candles made ?
=how do they make candles?