A:9
B:8
C:7
D:6
— There is somebody under the tree. Is it Mr. Lee?
— It ________ be Mr. Lee. He left for Beijing this morning.
京九铁路中段有一些明显的曲折,其主要考虑的区位因素是( )。
如图,下列条件中,一定能判断AB∥CD的是 ( )