模仿例句改写以下句子例句：This policeman is tall.But that policeman is ta

1.This street is clean
but that street is cleaner
this is the cleanest street I have even seen.
2.This man is old.
but that man is older.
he is the oldest man I have even seen
3..This river is long.
but that river is longer.
this is the longest river I have even seen