什么400次？
不过根据科学来说，the production of sperms should be 300 million per day, and the normal sperm production should be 100 million/ml. If a man produces less than 20 million/ml, it is considered to be sterile, which means he cannot make a woman pregnant. 由此看来可能不是次数多少，应该是ejaculate 多少。
随便聊聊，正好用到考试内容。 呵呵。
