相同条件下，气体A与氧气的质量比为2:1，体积比为4:1，气体A的相对分子质量是（ ）
A．16
B．17
C．44
D．64
答案：A
----I have never heard it _____ before. And you ?
----The same as you.
A．talking about
B．talked
C．talked of
D．being talked
下列链表中，其逻辑结构属于非线性结构的是
A．双向链表
B．带链的栈
C．二叉链表
D．循环链表
