六（1）班学生有一天请病假1人，参加校外数学竞赛2人，实到51人，缺席人数与全班人数的比是（ ）。
1：18
______肠管的病理变化局限于大肠( )。
A．大肠杆菌病
B．猪梭菌性肠炎
C．猪痢疾
D．猪传染性胃肠炎
E．猪瘟
The teacher， together with the students, _ __ discussing Reading Skills that ______ newly published in America.
A．are; were
B．is; were
C．are; was
D．is; was
