器物“豆”按年代变化的规律是（）
A.早期胖晚期瘦
B.早期瘦晚期胖
C.早期矮晚期高
D.早期高晚期矮
参考答案：C
已知x∈R，则x＞0的一个必要不充分条件是（ ）
A．x＞1
B．x＞-1
C．x＜1
D．x＜-1
Which of the following is the most appropriate title for the passage
What can be inferred about the annual world GDP
A．It is $3.5 trillion.B．It is $30.5 trillion.C．It is $35 trillion.D．It is $350 trillion.
