Do you ever think about what would or would not have happened if...? Make a chain story , using the following.
1) If I (not use) so much gas, I (not have) such a big gas bill.
2) If I (must not) pay my gas bill, I (not go) out in the rain.
3) If I (not go) out in the rain , I (not catch) a cold.
4) If I (not catch) a cold, I (not carry) a handkerchief.
5) If I (not carry) a handkerchief , I (not drop) it.
6) If I (not drop) my handkerchief , Juan (not pick) it up.
7) If Juan (not pick) up my handkerchief , we (never meet)