Thanks A LOT for TIG and Peter's quick reply and response. I really appreciate your patient help!!

Hello,

I am a beginner of sketchup. I tried to import a dwg file into sketchup, but I got some problems.

Since the imported drawings are in a group, I exploded the group by right click. Some lines are broken into pieces. I planned to make 3d model by a imported 2d dwg file, but the selected lines cannot be extruded by the push/pull function, no matter I made the lines into a group or not.

My questions:
1, Should I do something before editing the 2d drawing? And how can I extrude the 2d imported drawing by push/pull?
2, How to avoid the lines broken after importing dwg file?

Thanks a lot!

William