大脑发展的快速期是()
A.2~3岁
B.3~4岁
C.4~5岁
D.5~6岁
E.6~7岁
参考答案:D
解析:大脑发展的两个快速期是5~6岁和13岁左右。
We can't go to the concert ______ we are quite busy now. [ ]
A. though
B. until
C. because
D. so that
简述红外线的特性及在物证鉴定中的作用。