下列有关核酸的叙述中,不正确的是[ ]
A.核酸由C、H、O、N、P等元素组成
B.核酸的基本组成单位是DNA和RNA
C.核酸能控制蛋白质的合成
D.DNA主要存在于细胞核内
答案:B
你能回答吗?
1. How many students are there in your class?
___________________________________.
2. Do you have a library at school?
3. Do you have lunch at school?
4. Do you have a computer room?
常用风速传感器的测量范围是()。
A.0-30m/s
B.0-50m/s
C.0-60m/s
D.0-80m/s