变压器（）的效率高。
A、空载时比满负载时
B、1/2负载时比满负载时
C、空载时，比1/2负载时
D、满负载时比1/2负载时
参考答案：B
George Ernest Morrison, an Australian, traveled the "five-foot roads," or foot paths, from Shanghai to Rangoon in 1894, ______ China before it was engulfed in a century of revolution, war and political tumult.
A．witness
B．witnessed
C．witnessing
D．to witness
女，9岁，视力下降1月余，CT检查如图，最可能的诊断为（）
A．胶质瘤
B．脑膜瘤
C．脊索瘤
D．垂体瘤
E．颅咽管瘤
