计算机软件系统包括( )。A．系统软件和应用软件 B．编译系统和应用软件 C．数据

— You won't believe it. Sam. I have been chosen as an exchange student to China .   

—  Congratulations ! ___   [ ]

A. That's something.  

B. You did a good job .  

C. That's all right.    

D. You got it .

—Bob, it’s getting cold.     take a jacket with you?

---All right, Dad.

A．Why not

B．What about

C．How about

D．Why not to

endospore

某设备工程基础土石方工程量1000m³，其工作定额为5m³/工日，计划每大安排2班，每班10名工人工作，则该项工程活动的持续时间为( )天。

A．5

B．10

C．15

D．20

对须作整体热处理的设备，设计时要考虑哪些焊接附件问题？