太阳辐射能主要集中在
A.可见光波段
B.红外线波段
C.紫外线波段
D.紫外线和红外线波段
答案:A
本题考查太阳辐射。太阳辐射中能量最集中于可见光。
The old man asked Lucy to move to another chair__________he wanted to sit next to his wife.
A.although
B.unless
C.because
D.if
简述刑事证据学的研究方法。