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—...
呼气，膝部放松向胸部靠拢。Breathe out and ease your knees in toward your chest.屏住气息数五下，然后慢慢地呼气。Hold your breath for a count of five, then slowly breathe out.她接受了呼气测醉检查，结果超过了限定值。She was breathalysed and found to be over the limit....
The surly insolence of the waiters drove him into a rage,and he flung his serviette to the floor and stalked out of the restaurant.侍者们粗暴无礼的行为使得他怒不可遏,他将餐巾扔到地上,愤然走出餐厅。That old man is rather surly.这老头儿脾气倔.a surly mood坏脾气a s...