`2`.was introduced

`\rightarrow` BĐ `-` Thì QKĐ : S + was / were + V3 / PII ( by O )

`3`.had ... done ?

`\rightarrow` Before + S + Ved / V2 , S + had + V3 / PII ( `3 , 5` )

`4`.will be discussing

`\rightarrow` Thì TLTD : S + will be + V-ing ( `4 , 8` )

`\rightarrow` `DHNB` : this time next week

`5`.had deleted

`6`.rained / were playing

`\rightarrow` While + S + Ved / V2 , S + was / were + V-ing

`\rightarrow` Dùng để diễn tả hành động đang xảy ra , hành động xảy ra trong thời gian ngắn ( `6 , 9` )

`7`.had been / wasn't

`\rightarrow` Câu tường thuật : S + said + that + S + V ( lùi thì )

`\rightarrow` QKĐ `->` QKHT : S + had + V3 / PII

`\rightarrow` HTĐ `->` QKĐ ( ĐT Tobe - PĐ ) : S + wasn't / weren't + adj / n

`8`.will be sitting

`\rightarrow` `DHNB` : At this time next month

`9`.was chatting / disconnected

`\rightarrow` When + S + was / were + V-ing , S + Ved / V2

`10`.has attracted / opened

`\rightarrow` Thì HTHT : S + have / has + V3 / PII

`\rightarrow` Đi sau " since " chia theo thì QKĐ 

`\text{# Kirigiri}`