Question

He must work hard. He can get through this exam.
We should do this. It is our duty.
We stopped our car. We wanted to refill petrol.
( each question using infinitive)​

Answer 1

Answer:

He must work hard to get through this exam.

We should do this it's our duty. (Not sure if it's correct)

We stopped the car to refill the petrol.

Answer 2

Answer:

1:he must work hard to get through the exam.

2:it is our duty to do this.

3:we stopped our car to fill petrol.

Explanation:

all are usin infinitives