Passive form

[Belly T]

Do you mean like this, (B) is the passive of (A) ? If that's what you mean, then, yes, you're right: the statement in pink is incorrect.

(A) They threw a stone at him
(B) He was thrown a stone. <not the passive of (A)>

Both (A) and (B) are grammatically correct, but they don't share the same meaning, and it's for that reason alone that (B) cannot be the passive of (A). The passive of (A) looks like this,

(C) A stone was thrown at him.

Hope that helps.

So, how's it changed in meaning A and B, casiopea?
And why does it change like that?

[Casiopea]

So, how's it changed in meaning A and B, casiopea?
And why does it change like that?

It would be something like this:

Active: They threw a stone at him. <goal; he is the stone's target>
Passive: A stone was thrown at him. <goal; he is the stone's target>

Active: They threw him a stone. <recipient; he receives the stone>
Passive: He was thrown a stone. <recipient; he receives the stone>

Hope that helps.