适合塑料管材的重量验收法是（）
A.点件法
B.检斤验收法
C.理论换算法
D.整车复衡法
参考答案：C
______ abroad for more than two years, he returned to his hometown.
A．Studied
B．Studying
C．Having studied
D．To study
对于事先已确定发行条款的国债，我国仍采取承购包销方式，目前主要运用于不可上市流通的凭证式国债的发行。（ ）
