Pseudo-cleft sentences with the verbs of perception

I know we must use bare infinitives with these verbs in the Active.

e.g. I saw a lady cross the street.

There are other verbs with which we are supposed to use a bare infinitive in the Active.

e.g. I wanted him to leave. If we transform this sentence into the pseudo-cleft, we see for:

What I wanted was for him to leave.

My question is can we make pseudo-cleft sentences with the verbs of perception such as see or hear? Will these sentences contain the non-finite embedded clauses or will those be transformed into the finite ones? In the case they should remain non-finite, shall we use for or not?

What I saw was for a lady to cross the street. What I saw was a lady cross the street. What I saw was that a lady crossed the street.

May we use here a gerund? What I saw was a lady crossing the street.

Solution 1:

Both bare infinitive and -ing form (leaving aside for a moment the question of whether it is a participle or a gerund) are correct, with a slight difference of meaning/focus (i.e. did you see the whole action, or the activity in progress?)

So: I saw a lady cross the street (whole event, from kerb to kerb) and: I saw a lady crossing the street (perhaps just one instant of the activity in progress)

When it becomes a pseudo-cleft, only the -ing form is generally acceptable: What I saw was a lady crossing the street