Giải thích tại sao axit Clohiđric (HCL) có tính khử.

1: we were usually taken to the zoo by my uncle when we lived in HCM city (USED TO) => 2: He never drink beer now (USED TO) => 3: Rachel's mother paid for the meal . That was very kind of her (WHICH) => 4: Tom pushed Nick into the swimming pool. That seemed to amuse every one .( WHICH) =>