启动子是指()
A.转录区段的一个单位
B.转录起始点
C.翻译起始点
D.RNA-pol结合模板DNA的部位
E.远离结构基因能增强转录的序列
参考答案:D
You _______ worry about him. He will get well soon. [ ]
A. needn't
B. can't
C. mustn't
D. may not
藻类植物分布