I'm a little stupid

Originally, I wanted to ask some questions about a book which I've been reading recently. But I made a big mistake that I didn't finish the sentences of the text so that all the people didn't understand what I was saying. So, I prepare to write them again. I hope that someone can help me to answer my questions. Thank you.^_^

In the story, Sam, his mother and his friend were looking for his lost dog Champ. It's the sentence that I confused of below.

"Tasha suggested they go home and make posters with pictures of Champ. It was the procedure, or way of doing things, animal rescue had suggested when she had lost her cat."

I don't really know why the last sentence (animal had suggested when she had lost her cat) wasn't the passive voice？ If it can be said like that? (animal had been suggested when...). But there was a friend who said that it was wrong. Who can help me to explain it. Thank you. ^_^

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This sentence is in the passive voice because the writer wants to continue talking about the topic of the previous sentence (making posters with pictures of Champ).  Another way of writing it would be:

"Tasha suggested they go home and make posters with pictures of Champ. Animal Rescue had suggested this procedure, or way of doing things, Tasha had lost her cat." 

Both ways are correct, but the second way moves the focus of the sentence from making posters, to animal rescue. I think the first way sounds a little more natural.

I hope that is helpful! Ask me more questions if you want to.

I'm a little stupid

Originally, I wanted to ask some questions about a book which I've been reading recently. But I made a big mistake that I didn't finish the sentences of the text so that all the people didn't understand what I was saying. So, I prepare to write them again. I hope that someone can help me to answer my questions. Thank you.^_^

In the story, Sam, his mother and his friend were looking for his lost dog Champ. It's the sentence that I confused of below.

"Tasha suggested they go home and make posters with pictures of Champ. It was the procedure, or way of doing things, animal rescue had suggested when she had lost her cat."

I don't really know why the last sentence (animal rescue had suggested when she had lost her cat) wasn't the passive voice？ If it can be said like that? (animal rescue had been suggested when...). But there was a friend who said that it was wrong. Who can help me to explain it. Thank you. ^_^