我国规定齿轮分度圆上的标准压力角为（）。 A.15。 B.25。 C.20。 D.3

Read and judge. 阅读短文，判断正(T)误( F)。   

     David and his brother Greg don't go to school this morning. They go to school after lunch, at one

o’clock. They have math at one fifteen. David likes math. Because it is interesting. Greg doesn’t like

math. David and Greg have P. E. after math. They like P. E. Because it’s fun.  But Greg’s favourite

subject is art and David’s favourite subject is music. David plays the piano and the violin.   

( ) 1. David and Greg have P.E. after math.

( ) 2. David plays the piano.

( ) 3. They go to school this morning.

( ) 4. They don't like P. E. Because it’s boring.

( ) 5. Greg likes art.

下列哪一种物质不参与内源性凝血系统？（）

A.激活的Ⅻ因子

B.激活的Ⅹ因子

C.血小板因子3

D.Ⅴ因子

E.组织因子

我国神话保存的情况如何？

关于黄斑囊样变性，错误的是（）

A.多见于糖尿病视网膜病变、静脉阻塞、葡萄膜炎

B.液体蓄积在黄斑中央部的内丛状层

C.白内障术后黄斑水肿发生在术后4～6周

D.可保守治疗

E.可行玻璃体手术治疗

工字殿