声学研究表明,人耳常用声音范围的声压级在()DB,超过这个范围,将会给人带来烦恼,甚至造成耳的损伤。
A.35-70
B.35-75
C.40-80
D.45-80
参考答案:C
In France, people are not supposed to eat anything with your hands _____
bread. [ ]
A. beside
B. expect
C. besides
D. except
假设一棵二叉树的后序遍历序列为DGJHEBIFCA,中序遍历序列为DBGEHJACIF,则其前序遍历序列为______。