阅读材料，回答问题。 材料一漫画《墓碑》：希特勒正要求军队向东进攻。 材料二历

下列句子中，没有语意不明确的语病的一句是  

A．几个报刊编辑同一天向华老师约稿，够让华老师忙乎的了。

B．他背着监考老师和班长偷偷地把讲台上的资料拿下去了。

C．王叔叔的故事讲不完，今晚就讲到这里，早一点休息吧。

D．据现场消防人员介绍，起火房内已经从卧室门口烧到卫生间，屋内一片狼藉，墙壁都熏黑，不过没有人员受伤。

Ali is an antique dealer and one Saturday in November 2007 he put a vase in the window of his shop with a sign which stated ‘exceptional piece of 19th century pottery – on offer for ￡500’.Ben happened to notice the vase as he walked past the shop and thought he would like to have it. Unfortunately, as he was late for an important meeting, he could not go into the shop to buy it, but as soon as his meeting was finished he wrote to Ali agreeing to buy the vase for the stated price of ￡500. The letter was posted at 11:30 am.Later on the same day, Chet visited Ali’s shop and said he would like the vase but was only willing to pay ￡400 for it. Ali replied that he would accept ￡450 for the vase, but Chet insisted that he was only willing to pay ￡400 and left the shop. However, on his journey home Chet realised that ￡450 was actually a very good price for the vase and he immediately wrote to Ali agreeing to buy it for that price. His letter was posted at 12:30 pm.Just before closing time at 5 pm. Di came into Ali’s shop and she also offered ￡400 for the vase. This time Ali agreed to sell the vase at that price and Di promised to return the following Monday with the money.On the Monday morning Ali received both of the letters from Ben and Chet before Di could arrive to pay and collect the vase.Required:From the point of view of the law of contract advise Ali as to his legal relations with Ben, Chet and Di. (10 marks)

体外冲击波碎石（ESWL），对于肾结石最适合的是（）。

A.结石<3.5cm

B.结石<2.0cm

C.结石<1.5cm

D.结石<2.5cm

E.结石大小不受限制

霜的定义是什么？

在机组启动过程中，防止发生（），这不仅是机组安全运行的必要条件，而且也是保证机组能够顺利地启动起来的关键。