THE CORRECT ANSWER IS SEEN / SAW.DEFINITIONS

23. - TIEUBAOAN CONFUSED WORDSNHUNG TU GAY NHAM LAN
TIEUBAOAN CONFUSED WORDSNHUNG TU GAY NHAM LAN
23. The correct answer is seen / saw.Definitions:saw - v. past tense of seeseen - v. past participle of seeExplanation:A past participle in perfect tense requires a helping verb, or auxiliary verb (had, in this case), and the pure past tenseof a verb does not use auxiliary verbs. (About auxiliary verbs - see Did You Know? in question 4's Explanation)