— The earthquake in Wenchuan in 2008 killed people.
— We were sad to hear that.
A：thousands
B：thousands of
C：thousand of
D：two thousand of
明清时期，制瓷中心景德镇发展迅速，从事商品生产的民窑，其规模和数量逐渐超过专门为官府服务的官窑，出现了官府委托民窑代烧瓷器的现象。这段材料表明这一时期（ ）
