鉴别真、假性延髓麻痹的最可靠的体征是（）
A.有无饮水咳呛
B.舌能否伸出
C.有无声嘶
D.角膜反射阴性
E.咽反射是否存在
参考答案：E
如图所示，要使两灯串联，应闭合开关______，闭合开关S1和S3，两灯______联；为了避免短路，不能同时闭合开关______．
— Can you speak Chinese?
— Yes, I can. I _____ China for several years.
A. have been in B. have been to C. have gone to
