$\text{9}$ Lan didn't write to Maryam a month ago . 

$\text{10}$ He started living to Ha Noi when he was 13 . 

$\text{11}$ I didn't meet her a long time ago . 

$\text{12}$ How long ago did you learn French ? 

$\text{13}$ When did you buy this car ? 

$\text{14}$ How long have you started to lissten to classical music ? 

$\text{15}$ I have seen her for 10 years . 

→ S + didn't + V-inf + O 

→ Did +  S + V-inf + O ? 

→ How long ago + did +  S + V-inf + O ? 

→ When + did +  S + V-inf + O ? 

→ How long + has/have + S + Vpp + O ?