The doctor said we just had to let the disease run its course.医生说我们只能让这种病自生自灭。Seemingly, the cats had been living on their own for months.看样子，这些猫几个月来都是自生自灭。The government doesn't want to force inefficient firms to sink or swim too quickly.政府并不想迫使效率低的公司过快地自生自灭。