A.T. Robertson Commentary Acts 3:10

"and they took knowledge of him, that it was he that sat for alms at the Beautiful Gate of the temple; and they were filled with wonder and amazement at that which had happened unto him." — Acts 3:10 (ASV)

They took knowledge of him (επεγινωσκον). Imperfect active, inchoative, began to perceive.

Were filled (επλησθησαν). Effective first aorist passive.

At that which had happened (τω συμβεβηκοτ). Perfect active participle of συμβαινω.