Use conditionals with "would".
a)If the had had money at that time.(он бы помог нам)
b)If the were not so busy today.(Он бы помог нам)
c)If the weather were good,(мы бы поехали в горы)
d)If didn't rain(мы бы пошли в кино сегодня)
e)If they had known the truth(они бы не поверили ему)