用合适的关系词补全下面短文。 Robots are becoming more and more common amongst humans. Robots like Pepper have started working as assistants on the reception desk in Belgian hospitals 1. ________ are located in Liege and Ostend. The robots have begun working in both hospitals. The robot has a display screen on its chest and a spherical-shaped (球状的) head. It is the first robot 2. ________ has been used to greet people in a medical environment. The robot, 3. ________ is equipped with wheels under its white frame, is around 140cm in height. It can recognise the human voice in 20 languages and detect if it is talking to a man, woman or child. It is equipped with a facial recognition system as well. The robots 4. ________ have their components sent from Asia are assembled (组装) in France. A few small shops in a few large French malls have already tested a similar robot, generally used to carry out retail (零售) functions.