`1.` Mary suggested going for dinner

`-` Let's + V-inf + O

`=` S + suggested + V-ing + O

`2.` John is not old enough to understand the question

`-` S + be + too + adj + to V + O

`=` S + be not + adj + enough + to V + O

`3.` I haven't heard from my sister for 5 months 

`-` The last time + S + V-ed/V2 + was + TG + ago

`=` S + haven't/hasn't + PII + for + 1KTG

`4.` Mr.Thanh is the most careful person in the factory

`->` SS hơn nhất: S + be + the + adj-est/most adj + O

`5.` It was such a heavy box that my son couldn't carry it

`-` S + be + so + adj + that + 1 clause

`->` It + be + such + (a/an) + adj + N + that + 1 clause

`1. `Mary suggested going out for dinner.

`-` suggest + Ving: đề nghị làm việc gì

`2. `John is not old enough to understand the question.

`-`S + V + enough + noun + (for sb) + to V:  “đủ” để làm gì đó. 

`3.` I haven't heard from my sister for 5 months .

`-` The last time + S + Ved/V2 + was + [khoảng thời gian] + ago

`=`S + have/ has not (haven’t/ hasn’t) + Ved/V3 + for + khoảng thời gian : lần cuối ai đó làm gì

`4.` Mr Thanh is the most careful worker in the factory.

`-` S1 + tobe + the most + adj + S2 - so sánh  nhất

`-` Adj + N

`5.`It was such a heavy box that my son couldn’t carry it.

`-` S + to be + so + adj + that + S + V

`=`S + V + such + (a/an) adj + N + that + S + V