Many teenagers often go to school without ____ (have) breakfast. It is not good for them.
设a,b,c都是正实数,求证:aabbcc≥abca+b+c3
中国近代民族工业发展曲折而缓慢,在夹缝中求生存、图发展。中国近代民族工业所受的压迫不包括( )