Here is a look at what the San Francisco 49ers must do and can't do Sunday at Green Bay in the wild-card round:Must happen: Find the end zone. The 49ers have settled for field goals way too many times this season. The 49ers must finish drives. The Packers have a beatable defense and the 49ers must score touchdowns more than they score field goals.Can't happen: Let Aaron Rodgers take over. The 49ers' defense has been good, but it has been giving up some passing yards, especially in the past couple of weeks.