鼻窦黏膜下囊肿的MRI信号为（）
A.A
B.B
C.C
D.D
E.E
参考答案：B
解析：黏膜下囊肿因渗出液中含蛋白较低，呈长T1、长T2信号。
The result was not as good as expected but the ________ on his face told us that he was still very happy.
A．expression
B．impression
C．celebration
D．appearance
一个梯形，若上底延长3cm，面积就增加了6cm2，且变成了一个平行四边形，如果原梯形的上底是3cm，那么原梯形的面积是______cm2．
