2.(cooperate/cooperative/cooperation) a.China will with the USA in developing new medicines to prevent AIDS. Key:cooperate b.Professor Smith thanked his students for being so in the past semester. Key:cooperative 2. (cooperate/cooperative/cooperation) a. China will _____ with the USA in developing new medicines to prevent AIDS. Key: cooperate b. Professor Smith thanked his students for being so _____ in the past semester. Key: cooperative