在硬砂床或加固硬砂床上造型，通常是用压入模样的方法，直接得到底面型腔。

下图是世界上保存完好、最古老的一座单孔大石桥，其设计和主持建造者是

A．祖冲之

B．贾思勰

C．僧一行

D．李春

按照要求完成下列各题

1. What other things did he say?(改为同义句)

    ________ ________ did he say?

2. Why don't you go to the Great Wall?(改为同义句)

    ________ ________ go to the Great Wall?

3. She doesn't know where she should go.(改为简单句)

    She doesn't know ________ ________ ________.

4. My vacation is very exciting.(对画线部分提问)

    ________ was ________ vacation?

5. To take medicine on time is necessary.(改为同义句)

    ________ ________ ________ take medicine on time.

信号肽识别体可识别核小体。 ( )

异丙肾上腺素可用于（）

A．箭毒过量中毒解救 

B．有机磷中毒解救 

C．心脏骤停急救 

D．抗心律失常 

E．支气管痉挛

CO₂气体保护焊在野外风速大于（）m/s时，应采取防风措施。

A.1.5

B.2

C.2.5

D.3