【单选题】下列嘌呤核苷酸之间的转变,哪项是不能直接进行的?( )
【单选题】______ is meant that a conversational implicature is attached to the semantic content of what is said, not to the linguistic form.
【单选题】In conversational English 'is not' often ______ to 'isn't', consequently, 'was not' to 'wasn't', 'are not' to 'aren't'.
【简答题】从IMP合成GMP需要消耗______,而从IMP合成AMP需要消耗______作为能源物质。