【单选题】It is generally believed that constant reading and comprehending can ______ our mental ability of comprehension while physical exercise can help build up our body.
【单选题】We have spoken of marriage as a formal contract. It should be noted, however, that this contract does not【C1】______the same form. in different societies. In western societies the【C2】______of a man and...
【单选题】The pathways for degradation of pyrimidines generally lead to production and thus to _____ synthesis. Thymine, for example, is degraded to methylmalonylsemialdehyde, an intermediate of valine cataboli...