1.I (not/see) ________him since we left school 2.We (go)_______to the concert tonight 3.I (collect)_______stamps since I was a child 4.My parent (come )_______tomorrow to say with me for a few days

`1.` I (not/see) ________him since we left school

`->` ...... haven't seen ..... 

Có since : dấu hiệu của thì `HTHT : S + ` have/has (not) `+ PII `

`2` .We (go)_______to the concert tonight

`->` ... are going ....

Có tonight : dấu hiệu ` HTHT ` 

`3.` I (collect)_______stamps since I was a child

`->` .... collected....

`4.` My parent (come )_______tomorrow to say with me for a few days

`->` ...... will come...

Có tomorrow : dấu hiệu `HTĐ : S + ` will/won't + ...