В чем разница did it once и did it several times? И как правильно вставить глагол в каждом из случаев ?
1) I saw her (to slap) her son. (She did it several times)
2) I saw her (to slap) her son. (She did it once)
Буду очень благодарен.

1) I saw her slapping her son. (She did it several times)- действие в процессе( как длительность-вы это наблюдали)2) I saw her slap her son. (She did it once)-однократное действие( как факт)