4 KudoZ points awarded for this answer. Comment: "Revision: He must be sick, because he has lost all interest in eating, travelling, and painting. Discussion: Both NKWong and weiwei both agree that 病 is used as an adjective in this context. Although weiwei has provided a large number of examples for which I am grateful, NKWong appears to have better understood my confusion with regard to the use of 是. After all, where in English the verb "be" can introduce either a predicate adjective or noun, in Chinese the verb 是 is often not used to introduce adjectives. The Chinese greeting 你好嗎！is a common example of this! Acknowledgement: Certainly, I will incorporate both NKWong's explanation and weiwei's examples into my grammatical explanation. Also, special thanks to weiwei for her note on the meaning of 都沒有了, and both anastasia t and Tony Lai for their confirmation. As you can readily see, your input does make a difference! "