An idiom often cannot be understood by looking at the meaning of its separate words. ________, its meaning can be very different from the apparent meanings of its components.
第二部分:英语知识运用(共两节,满分45分)
第一节:单项选择(共15小题;每小题1分, 满分15分)
21.The experiment turned out to be______ failure, but as we know, Success often comes after_____ failure.