测定某mRNA分子中尿嘧啶占26%,腺嘌呤占18%,以这个mRNA反转录合成的DNA分子中,鸟嘌呤和胸腺嘧啶的比例分别是( )
A:18%、26%
B:28%、22%
C:26%、18%
D:44%、8%
两个射手彼此独立射击一目标,甲射中目标的概率为0.9,乙射中目标的概率为0.8,在一次射击中,甲、乙同时射中目标的概率是( )
Clerk: ____ I help you?
Mary: Yes, please. I want a sweater.
Clerk: What ____ do you want?
Mary: Blue.
Clerk: Here you are.
Mary: How ____ is it?
Clerk: Nine dollars.
Mary: I'll ____ it. Thanks.
Clerk: You're ____.
①滞留____ A.收留 B.停留
②赡养____ A.子女照顾父母 B.父母照顾子女
③憔悴____ A.瘦弱无力,脸色难看 B.烦恼焦虑,内心不安
④管窥蠡测____ A.眼光狭窄,见识短浅。 B.善于推测,目光远大
⑤一曝十寒____ A.天气寒冷 B.做事无恒心