建筑砂浆试验用料应从同一盘砂浆或同一车砂浆中取样。取样量不应少于试验所需量的（）。
参考答案：4倍
灰铸铁的五大元素：（）。
In the following essay, each blank has four choices. Choose the most suitable one from the four choices and write down in the answer sheet. Heterogeneous network environments consist of computer systems from (66) vendors that run (67) operating systems and communication protocols. An organization that (68) its computer resources is usually (69) the task of integrating its heterogeneous systems. Typically, each deparlment or division has defined its own network needs (70) OS, LAN topology, communication protocols, applications, and other components.
A．same
B．similar
C．different
D．difference
