依次填入下面一段文字横线处的语句，衔接最恰当的一组是（    ）历史上的扬州，属于“贵人多难”一类，______，______ _，_____，_______， ______。______。①且每遭蹂躏之后　  ②自隋至清一千多年间　  ③“大难不死，必有后福”用在扬州身上也是合适的   ④它总能顽强地恢复生气⑤虽屡遭兵火     ⑥却不掩其繁华的锦绣的气象

Your parents are very great. –Yes. They supported my schooling _______they were very poor at that time.

Sorry, the tickets have already been sold out.—Really? Maybe I _______ a little earlier.

Only when you try will you find how though the bottleneck may be ______ through.

Computers of this kind __________. They are out of stock (脱销) now.