Resposta :
a) If the weather were better yesterday, I'd go to the beach.
b) If Mary went to bed earlier, she wouldn't beso tired in the morning.
c) If the man drove slowly, he'd see the stop sign.
d) If I didn't miss the train, I would arrive in time. This one would be better in the third conditional though: if I hadn't missed the train, I would've arrived in time.