Answer based on context:

Coming off their win over the Falcons, the Patriots stayed at home for a Week 4 matchup against the Baltimore Ravens. The opening kickoff was fumbled by Ravens returner Chris Carr and recovered by McGowan at the Ravens' 12-yard line. However, the Patriots could not capitalize on the field position, settling for a 32-yard Gostkowski field goal to give them an early 3-0 lead. The Ravens began their first drive from their own 19-yard line and advanced on a 15-play drive, capping it with a 20-yard touchdown pass from quarterback Joe Flacco to wide receiver Derrick Mason. The Patriots responded with a 14-play drive of their own, going 76 yards before Brady scored on a 1-yard quarterback sneak to re-establish a Patriots lead at 10-7. The Ravens reached midfield on their next drive with a 22-yard reception by tight end Todd Heap, but the drive stalled at the Patriots' 38-yard line, setting up a punt by Sam Koch that gave the Patriots the ball at their own 9-yard line. Similarly, the Patriots reached Ravens' territory before having to punt; Hanson's punt landed in the end zone for a touchback. On the second play of the Ravens' ensuing drive, left tackle Jared Gaither injured his head falling into Flacco during a block; while he had motion in his extremities, the game was stopped for 15 minutes as Gaither was loaded onto a stretcher and taken to the hospital for tests. The Ravens' drive finished as a three-and-out. The Patriots then went 63 yards on six plays, extending their lead to 17-7 on a 12-yard touchdown run by Morris. With just under four minutes remaining in the half, the Ravens mounted a drive that reached the Patriots' 17-yard line with 1:17 left; Flacco was intercepted by Bodden to prevent the Ravens from scoring again before halftime. The Patriots first drive of the second half was aided by a 15-yard unsportsmanlike penalty on the Ravens' bench, but the Patriots were unable to capitalize as a Matt Light holding penalty and a Jarret Johnson sack of Brady forced a punt. Starting from their own 16-yard line, the Ravens advanced to their 45-yard line before a Wright sack of Flacco set up another punt. Kevin Faulk fielded the return but fumbled; Bodden recovered the fumble for the Patriots at their own 14-yard line. On the next play, Brady dropped back and was strip-sacked from his blind side by Terrell Suggs; defensive lineman Dwan Edwards recovered the fumble for the Ravens in the end zone for a touchdown, cutting the Patriots' lead to 17-14. Brady quickly recovered, hitting passes to Taylor for 13 yards, Aiken for 26 yards, and Moss for 20 yards to put the Patriots in the Ravens' red zone. Three plays later, Brady and Moss connected for their first touchdown of the season; the 14-yard strike extended the Patriots' lead to 24-14. The Ravens had similar success on his next drive, with Flacco hitting Mark Clayton on a 13-yard catch, Mason on a 20-yard catch, and then running back Ray Rice breaking a 50-yard rush to put the Ravens well into Patriots territory. A few plays later, Flacco kept pace with Brady on a 13-yard touchdown pass to running back Willis McGahee to cut the Patriots' lead to 24-21. The Patriots would control the ball for the next seven minutes, reaching the Ravens' 9-yard line on a second down. After two incomplete passes, the Patriots lined up in a field goal formation but the holder, Hanson, took a quick snap and passed to Baker, who had motioned outside of the formation. Baker was tackled around the first down marker, but was called for an illegal motion on the play. The Ravens challenged the ruling of a catch and the first down spot, as they would have declined the penalty if Baker had been short. The ruling was upheld and the Patriots took a 27-21 lead on a 33-yard Gostkowski field goal. After an exchange of three-and-outs, the Ravens mounted a drive with 3:32 left, reaching the Patriots' red zone with under a minute remaining. On third and fourth down, Flacco's passes fell incomplete to Mason and Clayton, ending the Ravens' hopes of a comeback. Brady then kneeled to hand the Ravens their first loss of the season and better the Patriots' record to 3-1.

How many field goals were scored in the first half?
1