A:reached , came to an end
B:was reached , put an end to
C:arrived at , bring to an end
D:was arrived at , came to an end
我国民间有句谚语:“水缸穿裙子,天就要下雨。”其中,“水缸穿裙子”是指盛水的水缸外表面出现了一层密度麻麻的小水珠。小水珠是由( )