Question

Wren & Martin Ex 41-8 change to passive-

"They saw the storm approaching."
The key says-
"The storm was seen approaching." (seems perfect to me.)

In that case,

"They saw the clouds thundering." should be,
"The clouds were seen thundering."

What is the correct answer,

"The thundering clouds were seen" or "The clouds were seen thundering." ?

thanks

Answer 1

"The storm was seen approaching" is not in the perfect tense. It's a straightforward passive. The perfect tenses always have some form of the verb "to have" followed by the past participle. The passive always has some form of the verb "to be" followed by the past participle.

These are perfect forms of that sentence --
They had seen the storm approaching.
They have seen the storm approaching.
They will have seen the storm approaching.


"They saw the clouds thundering" converts to passive, as with the storm sentence, with a verb change from "saw" to (in this case, because it's plural) "were seen." Because of the way we tend to think of the phrase "thundering clouds," I think most native speakers would say "The thundering clouds were seen (by them)." Note that the "by them" is not absolutely necessary. But you could also say "The clouds were seen thundering." That is certainly closer to the original sentence.

The main point here is to shift the verb from active to passive, and to shift the object of the action in the active sentence to be the subject of the sentence in the passive version.

Answer 2

I should have written (seems perfect to me) as (seems correct).

Well, my doubt on "clouds thundering" and "thundering clouds" is clear.

Mille Grazie...Ciao...