题型：问答题 从方框中选择适当的短语并用其正确形式完成句子。look down at go the right way go through,on the edge of at the bottom of look across to1. "Don't stand the canyon. It's dangerous," the tour guide said. 2. You must a big gate to enter the house. 3. Have you ever heard the story about a frog a well?4. I the other side of the road, but saw nothing. 5. Mr Brown didn't know if he was .6. I the small house 100 metres below me. 查看答案
题型：问答题 MPEG-1视频编码标准中定义了（）种不同类型的视频帧，其中（）在各种帧类型中数据量居中，而数据量最小的（）在之前的H.261标准中并没有定义，能够直接作为索引和访问点的是（）。能够直接作为索引和访问点的是（）。A．I帧B．B帧C．Y帧D．P帧 查看答案