如图,四边形ABCD内接于半圆O,已知∠ADC=140°,则∠AOC的大小是( )
A:40°
B:60°
C:70°
D:80°
甲、乙、丙三种固体物质的溶解度曲线如图所示.回答下列问题:
下列常见的生活用品中,主要使用合成纤维材料制成的是( )
My husband came home from work at four o'clock, his task ___ early today.