引起脑梗死最常见的原因是（）
A.脑细小动脉硬化
B.脑动脉粥样硬化
C.脑动脉栓塞
D.脑出血
E.肿瘤
参考答案：B
David apologized to me yesterday. __, I won't forgive him for it was not the first time that he had hurt me.
A．If so
B．If ever
C．Even so
D．Even though
在使用扫描仪扫描文字时，分辨率在（）dpi时扫描效果最好。
A、200
B、300
C、400
D、600
