Thinking Step 2: 推理第一个人。如果他不想要，他会直接说“不”（因为只要有一个不要，全称命题为假）。他说“不知道”，说明他自己想要，但他不确定后面两个人想不想要。
A planetary parade, which occurs when several planets appear to align on one side of the Sun from Earth's perspective, will be visible in the UK again from sunset on Saturday.
，这一点在爱思助手下载最新版本中也有详细论述
You can see it hiding in your execution plans:
MacBook Air delivers the perfect combination of performance and portability for everyone from college students to creative professionals, as well as consumers — and it’s the most popular laptop for business users.