单选题 The main purpose of this passage is to ______.

A、 teach children how to learn to produce and experience certain emotions
B、 give the common reader a general description of two basic kinds of learning
C、 give parents some advice on how to modify their children's emotions through learning
D、 discuss with psychologists how positive and negative feelings are produced

【正确答案】 B

【答案解析】[注释] 第一段第四行提及there are two basic processes by which learning takes place，下文就这句话展开论述。