You may register to take one or both subtests of a single test field per test session at a test center. If you select both subtests in one registration, both subtests will be administered in one four-hour test session at a test center. Within the test session, the subtests are not individually timed and you may spend as much time as you choose on each subtest. If you are taking both subtests, you may also choose to submit a separate registration for each subtest, which allows you to schedule the subtests separately (e.g., on different days), each in its own four-hour test session at a test center.