The Natural Approach claims that the transition from pre-production input to a stage in which students begin to speak is simple if opportunities for production are made available gradually within the normal ________activities.
comprehension
自然法认为， 在正常的理解性活动范围内， 只要机会合适， 从语言输入的试验阶段逐渐转移到学生开始口头说的阶段是很容易的。