Your forced laughing is more noticeable than you think, mainly because ______.

参考解析：

细节理解题。根据第三段前两句“The most prominent factor distinguishing real laughter from fake laughter is duration—or, more specifically, the number of breaths taken in between sounds. Seeing as it takes more effort and concentration to fake a laugh as opposed to do it genuinely. people tend to pause more in between their ‘ha-ha’s’ when they’re faking it”可知，区分真笑和假笑最重要的因素是持续时间，或者更具体地说，是声音之间的呼吸次数。假笑比真笑需要更多的努力和注意力，所以人们在假装笑的时候，往往会在“哈哈大笑”的间隙停顿更多，由此可知，你的假笑比你想象的更引人注目，这主要是因为当你试图假笑时，你会做更多的呼吸，故选B。