另两个为胸腺嘧啶和胞嘧啶, 即称为嘧啶的单环结构.The other two, thymine and cytosine, are single ring structures called pyrimidines.嘌呤为嘧啶取代或嘧啶为嘌呤所取代,叫做颠换.The substitution of a purine for a pyrimidine, or vice versa is a transversion.本文研究氟脲嘧啶(5—...
The ship would lie there mirrored in a perfectly unmoving glossy sea.船会停靠在那里,映衬在一片波澜不兴的湛蓝海水之中。Their progress at work was mirrored by their children's educational advance.子女在学业上有所进步,他们在工作上也就会有所起色。She made a cryptic c...