你们俩是在树林里分开的吗?Did the two of you split up in the woods?它们是合在一起还是分开的?Are they joined together or separate?昨晚他们什么时候分开的?When did they separate last night?...
只有4种: 腺嘌呤 、 胸腺嘧啶 、 鸟嘌呤和胞核嘧啶.There are just four kinds: adenine, thymine, guanine and cytosine.腺嘌呤:在DNA和RNA中发现的含氮的碱基 ( 6 - 氨基嘌呤 ).Adenine A nitrogenous base ( 6 - amino - purine ) found in DNA and RNA.尿嘧啶 -- 核糖核酸中的一种嘧啶,与腺...