The USMLE Step 1 exam is continuously updated, and so is the UWorld QBank. A PDF circulating on Google Drive is almost certainly an older version. You would be studying from outdated questions and explanations, which could harm your preparation for the exam you will take.
Highlighting text in a PDF encourages passive reading, which reduces information retention compared to actively selecting answers under a timer. uworld step 1 pdf google drive link
Many students seek these links to avoid the high cost of official subscriptions, which can range from to over $600 for a year with the medical library. The USMLE Step 1 exam is continuously updated,