4.He drives more carelessly than he used to. A He doesn't drive as carefully as he used to . B. He doesn't drive carefully than he used to. C .He doesn't drive as carefully than he used to.

`4`.A

`\rightarrow` So sánh ngang bằng ( Trạng từ ) : S1 + V + as + adv + as + S2

`\rightarrow` Thì HTĐ ( CPĐ ) : S + don't / doesn't + V

`\rightarrow` `\text{S + used to + V :}` Đã từng

`\text{@ TheFox}`