The children will climb the hill if it ___________ tomorrow.
A:won't rain
B:didn't rain
C:isn't raining
D:doesn't rain
在地理环境中,山脉常常成为一种地理分界线。下列山脉与其地理界线的对应关系中,正确的是( )
化脓的伤口中脓液的主要成分是( )