(a) John's friends admired at / of / about his new bicycle.
(b) John's friends admired at / of / about him when he show off his skills (in front of them)
Vincent Teo Can I write, (a) John's friends admired at / of / about his new bicycle. (b) John's friends admired at / of / about him when he show off his skills (in front of them).
(b) John's friends admired at / of / about him when he show off his skills (in front of them).