`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 + ...