Error (10500): VHDL syntax error at 1.vhd(48) near text ":"; expecting ";" 标红处怎么修改？

counter0pro:process(reset,clk)
begin
if reset='1'then
counter0<=x"00";
elsif clk'event and clk='1'then
if counterO=x"09"then
counter0<=x"00";
else
counter0<=counter0+1;
end if;
end if;
end process;