`4.`She told us that they had studied that kind of plant for two months.

`=>`Form : S + told + O ( that ) + S + V lùi thì...

- have studied `->`had studied ( Lùi thì )

- this `->`that

`5.`Mr. Vinh said that they didn't open the laboratory that day.

`=>`Form : S + said ( that ) + S + V lùi thì...

- We `->`They ( Đổi ngôi )

- don't `->`didn't ( Lùi thì )

- today `->`that day ( Chuyển đổi thời gian )

`6.`Nick said that he was finding evidence for his research then.

`=>`Form : S + said ( that ) + S + V lùi thì...

- I `->`He ( Đổi ngôi )

- 'm finding `->`was finding ( Lùi thì )

- my `->`his

- now `->`then ( Chuyển đổi thời gian ) 

`7.`I told Mary that she might be late for the workshop that atternoon.

`=>`Form : S + told + O ( that ) + S + V lùi thì...

- You `->`She ( Đổi ngôi )

- may `->`might

- this afternoon `->`that afternoon

`8.`Dr. Thomas said that he hadn’t taught Earth Science the previous year.

`=>`Form : S + said ( that ) + S + V lùi thì...

- I `->`He ( Đổi ngôi )

- didn't teach `->`hadn't taught ( Quá khứ đơn `->`Quá khứ hoàn thành )

- last year `->`the previous year

`9.`Minh said to me that they would start collecting the data the following month.

`=>`Form : S + said to O ( that ) + S + V lùi thì...

- We `->`They ( Đổi ngôi )

- will `->`would

- next month `->`the following month/ the next month

`10.`Jane said that her sister wasn’t leaving for London that night.

`=>`Form : S + said ( that ) + S + V lùi thì...

- My sister `->`Her sister

- isn't leaving `->`wasn't leaving ( Lùi thì )

- tonight `->`that night