简述《史记》的体裁与体例。

在△ABC中，∠A：∠B：∠C=2：3：4，则∠A=______，∠C=______．

根据上句完成下句，使两句意思表达基本相同。

1. Yesterday afternoon it rained heavily, so I borrowed an umbrella from Ed. 

    Yesterday afternoon it rained heavily, so Ed _____ _____ an umbrella.

2. Allan went to play football with his friends at once after he finished his homework.

    _____ _____ _____ he finished his homework, Allan went to. play football with his friends.

在计算银行风险加总的过程中，只需要把单笔交易的风险计量准确，再直接加总，就可以获得合理的风险加总结果。（）

压力钢管的布置形式，一般最常见的有坝内式、（）及露天式三种。

A、涵洞式

B、隧洞式

C、坝外式

D、组合式

在Visual Basic中，定义变量A为整型变量的语句正确的是______。

A．DIM A AS CHAR

B．DIM A AS BOOL

C．DIM A AS INTEGER

D．DIM A AS DATE