玉米( 2n=20 )种群中偶尔会出现一株三体植物( 5 号染色体有 3 条)。在减数分裂时,这三条染色体的任意两条向细胞一极移动,剩下一条移向另一极,细胞中其余同源染色体正常分离。若控制玉米高杆、矮杆的基因分别是 A 、 a ,且当体细胞中 a 基因数多于 A 基因时, A 基因不能表达。下列关于三体玉米(基因型 Aaa )的叙述,错误的是
【简答题】Translate the words in brackets in the following sentences into English, using phrasal verbs in “ V+ prep. +N” . (动词+介词+宾语) 1) He _____________ 工作到很晚。(work) 2) If repairs are needed in the equipment, ...
【简答题】Church as we use the word refers to all religious institutions, ____ they Christian, Islamic, Buddhist, Jewish, and so on. A. be B. being C. were D. are