A keyboard (110) includes a base board (116), keys (112), pitfalls (120) and a mode control mechanism (118). The keys (112) include cups (1124), and the mode control mechanism (118) may switch the keyboard (110) especially the key cups (1124) between different modes. In case that the keyboard (110) is not in use, these cups (1124) can be received in the pitfalls (120) to reduce the profile of the keyboard (110). In case that the keyboard (110) is to be used, the keys (112) may be raised up and arranged on the base board (116) in order to enable long keystroke and provide good typing experience.