一头牛的体重约500千克，四头牛约重______吨．
500×4=2000（千克）
2000千克=2吨．
故答案为：2．
-Why do you look sad?
-There are so many problems _______ [ ]
A. remained to be settled
B. remained setting
C. remaining to settle
D. remaining to be settled
用户用计算机高级语言编写的程序，通常称为( )。
A．汇编程序
B．目标程序
C．源程序
D．二进制代码程序
