临床上主要发生于10~30日龄仔猪,临床上拉白色浆糊样稀粪,死亡率低的病可能是()
A.仔猪黄痢
B.仔猪白痢
C.猪痢疾
D.猪传染性胃肠炎
E.仔猪红痢
参考答案:B
Last summer holidays, he went to the countryside and worked together with farmers.In this way
he learnt________from farmers .[ ]
A. a great many
B. a great deal
C. scores of
D. much more
平行布置管道上的阀门,其中心线尽量取齐。手轮间的净距不应小于()m。
A.100
B.200
C.300
D.400