39. Its two years since I last spoke to her. - I havent___________________________________________________________. 40. Going swimming in the river in the summer is interesting. - It___________________________________________________ 41.We were late for school because of the heavy rain. - Because it_____________________________________________________________. 42. My mother used to make us clean the house. - We used_______________________________________________________________.

`39`.I haven't spoken to her for two years

`\rightarrow` Thì HTHT : S + haven't / hasn't + VpII

`\rightarrow` For + Khoảng thời gian : Bao lâu

`40`.It is interesting to go swimming in the river in the summer 

`\rightarrow` It is ( not ) + adj ( for O ) + to do sth : Như thế nào để làm gì

`41`.Because it rained heavily , we were late for school

`\rightarrow` Because + C1 + C2 : Bởi vì

`=>` Dùng để chỉ nguyên nhân , lý do

`42`.We used to be made to clean the house by my mother

`\rightarrow` BĐ `-` used to : S + used to be + VpII ( by O )

`\rightarrow` be made + to do sth : Bị bắt làm gì

`\text{# Eternal}`