Cho%20s%EF%BF%BD%EF%BF%BD%20%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%20chuy%EF%BF%BD%EF%BF%BD%EF%BF%BDn%20h%EF%BF%BD%EF%BF%BDa%20sau:%20Tinh%20b%EF%BF%BD%EF%BF%BD%EF%BF%BDt%20metyl%20axetat