1.Without this treatment, the patient would have died
→ If.... it hadn’t been for this treatment, the patient would have died. ....
2. As she is often absent from class, she can not keep pace with her classmate.
→If.. she weren't absent from class, she could keep pace with her classmates....
3.The wind is blowing hard, so i will not take the boat out for ride
→If.. the wind weren't/wasn't blowing hard, I would take the boat out for a ride.....
1.Without this treatment, the patient would have died
→ If.......it hadn't been for this treatment, the patient would have died
2. As she is often absent from class, she can not keep pace with her classmate.
→If.....she weren't often absent from class, she could keep pace with her classmate.
3.The wind is blowing hard, so i will not take the boat out for ride
→If..the wind weren't ....blowing hard, i would take the boat out for ride