Virtual reality technology refers to a simulation system that can create and experience a virtual world. It uses computer-generated interactive three-dimensional environments to provide users with visual, auditory, tactile and other sensory simulations, thereby making people immersive sense, this is an immersive experience with a 360-degree viewing angle. According to the definition above, Which of the following options are used by virtual reality technology:. ['Zhang San video chats with his father in Paris via a computer and sees the Eiffel Tower in person.', 'Li Si used his mobile phone WeChat to video chat with his wife, and he heard his son recite ancient poems.', 'Liu Wu put on a special helmet to buy a desk online, and can fully experience the effect of the desk in the study.', 'Wang Er used a tablet computer to watch a video of his classmates traveling in Tibet and felt that he had also arrived at the Potala Palace.']