. –CLAUSE) PRESENT SIMPLE ZERO CONDITIONAL (MAIN CLAUSE) FUTURE SIMPLE CAN / MUST/ MAY +INF. (IF –CLAUSE) PRESENT SIMPLE 1 st CONDITIONAL (MAIN CLAUSE) CONDITONAL. –CLAUSE) PAST SIMPLE 2 nd CONDITIONAL (MAIN CLAUSE) CONDITONAL PERFECT COULD / MIGHT +HAVE+P.P. (IF –CLAUSE) PAST PERFECT 3 rd CONDITIONAL