be baffled; be greatly(/extremely) puzzled; be confounded (/per plexed); be unable to make head or tail of sth; be in a puzzle about sth; be not a little bewildered;in great wonder
❍ 我对这事感到～。I am quite puzzled about this matter.
大惑不解dà huò bù jiě
原指一辈子迷惑不解。现多指对某事怀疑，不理解。be extremely puzzled, be great puzzled, in great wonder, be unable to make head of tail of sth., be baffled, be a puzzle to sb.