I used QGIS 3.2 to load OSM data obtained from Geofabrik as
Layer/ Add Layer/ Add Vector Layer
The problem is that QGIS does not show roads completely compared to the OpenStreetMap website. I converted the .osm format to .xml and searched for the ID of missing line segments from the OSM website. I found out the tag with the specified ID exists in the XML file so the Geofabrik data is the same as OSM webpage. I also installed QuickOSM plugin in QGIS with no success of loading the whole data. Is it some bugs in QGIS or something else?