The dead rate is _____ pigs and recovery
题型：选择题
问题：
The dead rate is _____ pigs and recovery usually ______ within 7-10 days.
A low in; occurs B.rich in;happens
C.high in; came about D.poor in;took place
The dead rate is _____ pigs and recovery usually ______ within 7-10 days.
A low in; occurs B.rich in;happens
C.high in; came about D.poor in;took place