未知题型 We should see the events in their historical ________ before we draw any conclusion.A respectiveB retrospectiveC prospectiveD perspective

未知题型 Lack of confidence is the biggest ________ to his success.A barrierB obstacleC flawD drawback

未知题型 She had regular treatment ________ for the next two years, and was still making progress.A sessionsB processionsC specificationsD procedures