Experts call on parents, especially ________ of the broken families, ________ the full responsibilities

and better care and love for children.[ ]

A. that; to burden  

B. them; to take on

C. those; shouldering  

D. those; to shoulder

( )适用于工作项目较少，工艺过程比较简单的工程。

A．单代号网络计划

B．双代号网络计划

C．单代号搭接网络计划

D．双代号时标网络计划