This is day four of a 40-day respite before the 49ers gather for Training Camp 2018. Thus, a perfect time to review what we learned during the team’s off-season program, which ended last Thursday with a three-day minicamp. 1. The offense lags badly behind the defense. In off-season practices open to the media, the offense struggled mightily, including last Wednesday, when the offense threw three straight interceptions on consecutive drives. 2. The above is not surprising because the defense is simplified and the 49ers quarterbacks are relatively new to the system. 3. The 49ers receiving corps is improved, however, the group lacks a big receiving target. 4. Fifth-round pick Trent