肛瘘的主要症状是:()
A.便血、便秘、脱出
B.肛周流脓、疼痛、瘙痒
C.肛门肿物、剧痛、不出血
D.周期性疼痛、便血、便秘
E.肛门异物感、肿胀、疼痛
参考答案:B
My classmate Andrew went to Vancouver , Canada in 2005 , and_____since .
A.has not heard of
B.had not heard of
C.has not been heard of
D.had not been heard of
楼梯是由()组成。
A、楼梯梯段
B、楼层平台
C、中间平台
D、栏杆(或栏板)和扶手