魏晋南北朝时期的手工业技术有所进步,下列各项能反映这一特点的是( )①吴培养出八辈之蚕,蜀盛产蜀锦 ②发明和推广低温炼钢技术
My mind wasn’t on what he was saying, so I’m afraid I _____ half of it. A. was missing B. had missed C. will miss D. missed
Lingling and Betty ________ like _______ on the playground. A. doesn’t, run B. don’t, run C. don't, running D.doesn’t , running
下列有关叙述中,正确的是A.20℃,100g水中溶解30g NaCl,所以20℃时NaCl的溶解度是30 gB.NH4NO3固体溶于水,吸收热量C.饱和溶液降温后,都有溶质析出D
—Can I ask you a few straightforward questions about yourself? —No problem.I like ______ when people are open and direct. A.that B.this
布袋中装有2个红球,3个白球,5个黑球,它们除颜色外均相同,则从袋中任意摸出一个球是白球的概率是_________.
4溴苯乙酮酸乙酯(G)是合成药物的重要中间体。工业上合成路线如下: 已知:加热时,在NaOH溶液中很难水解。 (1)B→C的反应类型是________;E的结构简式
花生是人们常吃的一种食品。花生果壳内的种子(即花生仁)有大有小,颜色也有深红、浅红之分,这与其品种及种植的土壤有关,以下说法正确的是