有头疽初起的局部症状是（）
A.粟粒样脓头
B.肿硬如钉丁
C.漫肿而无头
D.腐烂如莲蓬
E.腐烂大于尺
参考答案：A
When I got to the meeting room, the meet for half an hour.[ ]
A. has begun
B. had been on
C. had begun
D. has been on
蜗杆传动因为齿间发热量大，所以（）常用减摩材料制造，以减小磨损。
A.蜗杆
B.蜗轮
C.轴承
D.轴
