REWRITE 1. She started living in London 20 years ago. -> She has 2. I last wrote to him a week ago. -> I havent

1. She has lived in London for 20 years.  

[Kiến thức: Chuyển đổi thì]

S+start+V-ing+O+time+ago (QKĐ)-> S+have/has+V3/ed+O+for+time (HTHT). 

``

2. I haven't written to him for a week. 

[Kiến thức: Chuyển đổi thì]

S+last+V2/ed+O+time+ago (QKĐ) -> S+haven't/hasn't+V3/ed+O+for+time (HTHT).