新鲜溶剂油来自()。
A.乙烯销售
B.乙烯厂
C.炼厂
D.外购
参考答案:C
根据要求完成句子,每空填一词。
1. He is never here. (改为反义句)
He is _____ here.
2. I like the novel by Smith. (把I改为Tony)
Tony _____ the novel by Smith.
3. She does her homework at school. (改为否定句)
She _____ _____ her homework at school.
下列有关基因的说法不正确的是[ ]
A.基因都是通过控制酶的合成控制生物性状
B.基因是有遗传效应的DNA或RNA片段
C.基因以一定的次序排列在染色体上
D.基因是生物遗传的基本功能单位