速率区带法要求样品粒子的密度与梯度液柱中任一点密度的关系必须是（）。A.大于 B.大

读短文，判断正(√)误(×)。

      Welcome to the Children's Centre. You can do many things here. Look, there are many children. This is

Chen Jie. She's drawing pictures. Mike is watching insects. Amy is reading a storybook. Wu Yifan is playing

chess with a man. Who's the man? He's Mr Black, Wu Yifan's math teacher. He's a smart man. John and Sarah

are taking pictures. Where's Bai Ling? Look! She's over there. She's writing a report. Her sister is singing and

playing the piano.

( ) 1. Chen Jie is taking pictures.

( ) 2. Amy is reading a book.

( ) 3. Mr Black is playing chess.

( ) 4. John is drawing pictures.

( ) 5. Bai Ling is writing an e-mail.

胸腰椎椎体压缩骨折，压缩不到1/3，首选的治疗方法是

A．卧硬板床

B．两桌法过仰复位

C．手术内固定

D．石膏背心外固定

E．手术椎体融合

下列各句中没有错别字的一句是（）。

A．天津杨柳青镇是年画的发祥地，每年春节前后，海内外游客都纷至踏来，感受腊月新春的民俗风情

B．每当谁做了有益于公众的事，社会就理所当然地给谁以肯定和称诵，谁也就会因此赢得巨大的荣誉

C．经过一年的调查取证，检查机关终于查清了这家公司的总经理循私舞弊而导致公司倒闭的事实

D．感知明快的人，善于洞察前景，知微见著；感知迟钝的人，往往过于拘泥和死板，只看到过去而看不到将来

上级账户余额不足向下归集时的归集模式有（）.

A.随机处理。

B.账户优先。

C.先小后大和先大后小。

D.加权平均。

如果是已奉命进入一级战备，从接到上级命令开始到部队完成行动准备。共有（）时间。

A.5

B.6

C.7

D.8