1) Unless he does morning exercise. He wont help good helth
-> If he  does morning exercise,he will elp good helth
2) He cant come because she is seriously ill
-> Unless she isn seriously ill,he can come
3) He couldnt come because they were busy
-> If they were busy, he could come
4) The couldnt go fast because of the fog
-> If itwwasn't fog, he could go fasst
5) The storm prevented us from driving fast
-> we would have drived faats unless  the storm prevented us