Question

1) Where wpuld you go if you ..... a rich person?
a)was
b) is
c) are
d)were
e) be

2) If he ...... them, they ...... saind "no".
a) has asked/will
b) had asked/will have
c) had ask/would have
d) had asked/would have
e) none of the above

3)Water ..... if you ...... it to 100°C
a)boil/heat
b) boils/heat
c)boiled/ heat
d) boils/heats
e) "b" e "d"

Answer 1

1 Where would you go if you were a rich person? (d)
2 If he had asked them, they would have said no. (d)
3 Water boils if you heats it to 100ºC

A regra é simples, decore esta mnemónica:
Present -> Present
Present -> Future
Past Simple -> Conditional 
Paster Perfect -> Conditional Perfect 

Saudações.