题目

How to protect children web fans from unsuitable materials (材料) on-line while encouraging them to use the Internet has long been discussed in the US. For some time, the Internet seems like a forest, filled with danger for children. But forests have wonders as well as dangers, and with good guides, some education and a few precautions (预防措施) ,the wilds of the Internet can be safely navigated (航行). “Children have to be on-line. If we tell our children they can’t have chances to the Internet, we’re cutting them off from their future,” said an expert. Most children 已知是两条不同的直线，是三个不同的平面，下列命题中错误的是（  ）A．若，则∥B．若∥，∥，则∥C．若∥，则∥D．若是异面直线，∥，∥，则∥