单选题 Traffic police in Cambodia have not _______ traffic laws for four months due to the election. enforce B. enforced C. enforcement D. enforceable

单选题 Concerns over the online social network’s new privacy policy have led some faithful users to _________ their accounts.

单选题 As responsible adults, we must _______ all the consequences of our actions, even the unintended ones.

单选题 With tons of imitation (仿造的), synthetic (人造的) diamonds pouring into the market, it has become necessary to establish a diamond _________ method.

单选题 The essence of ________ is the attempt to control the animal instincts of humans to build a better life

单选题 The _____________ cough and headache led to his continual insomnia (失眠).

单选题 The change in the economic environment makes him in ________ need of big investment.

单选题 Chinook salmon (奇努克鲑) hatch (孵化) in freshwater rivers but _______ out to the Ocean.